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QP34  .L63  Hygienic  physiology. 


RECAP 


Columbia  SSnitiersitp 
in  tlje  Citp  of  iSetu  gorfe 

COLLEGE  OF  PHYSICIANS 
AND   SURGEONS 


Reference  Library 

Given  by 


ADULT    HUMAN    SKELETON. 

1,  skull  (cranium). 

2,  collar-bone  (clav'icle) . 

3,  shoulder-joint,   composed  of 

one  end  of  the  clavicle,  a 
portion  of  the  shoulder- 
blade,  and  the  head  of  the 
hu'merus. 

4,  humerus. 

5,  radius ;    in  the  left   arm   it 

crosses  the  ulna. 

6,  ulna,  at  elbow-joint. 

7,  edge  of  left  shoulder-blade 

(scap'ula). 

8,  breast-bone  (sternum) . 

9,  lumbar  portion  of  spinal  col- 

umn. 

10,  is  on  that  part  of  the  pelvis 

which  is  called  the  il'ium, 
The  left  hand  rests  on  the 
projection  felt  at  the  hip. 

11,  sa'crum,  which  forms  the  pos- 

terior boundary  of  the  true 
pelvis. 

12,  hip-joint. 

13,  shaft  of  thigh-bone  (femur) . 

14,  knee-pan  (patella). 

15,  shin-bone  (tib'ia). 

16,  fib'ula. 


From  a  photograph  of  the  skeleton  in  the  Anatomical 
Museum  of  the  College  of  Physicians  and  Surgeons, 
New  York  City. 


HYGIENIC  PHYSIOLOGY 


a  EtxtMook 


FOR    THE   USE    OF  SCHOOLS 


BY 


D.   F.   LINCOLN,   M.D. 

Late  Secretary  Health  Department  of  American  Social 

Science  Association;  Author  op  "School  and 

Industrial  Hygiene,"  Etc. 


5j««<C-r— - 


BOSTON,  U.S.A. 
GINN   &  COMPANY,  PUBLISHERS 

1893 


Copyright,  1891, 
By  D.  F.  LINCOLN. 


All  Rights  Reserved. 


LG3 


TrPOGRAPHY  BY  J.   S.   CUSHING  &  Co.,  BOSTON,  U.S.A. 

Presswork  by  Gtinn  &  Co.,  Boston,  U.S.A. 


PREFACE. 


The  work  which  is  here  presented  was  planned  with  the 
object  of  giving  our  young  people  something  rather  more 
directly  practical  than  is  usually  found  in  school  physiologies. 

The  execution  of  this  plan  will  be  found  to  vary  somewhat 
in  different  parts  of  the  book,  owing  to  the  nature  of  the 
different  subjects  treated.  Thus,  under  "Food  and  Digestion," 
the  reader  will  find  a  minimum  of  anatomical  detail,  with  a 
good  deal  regarding  the  different  kinds  of  food  and  the  practi- 
cal rules  of  diet;  while  in  some  other  parts  anatomical  and 
physiological  data  predominate. 

The  structure  of  our  own  bodies  is  undeniably  an  interesting 
subject  of  itself.  Nor  can  it  be  advantageously  omitted  from 
a  work  like  the  present,  forming  as  it  does  the  basis  for 
hygienic  teaching.  The  merit  of  the  book  will  be  seen,  there- 
fore, to  be  largely  a  matter  of  proportion. 

The  subject  of  alcoholic  drinks  has  been  treated  in  a  separate 
chapter,  with  such  special  additions  at  the  end  of  other  chap- 
ters as  their  respective  subjects  require.  The  views  presented 
are  intended  to  be  such  as  will  generally  be  admitted  among 
medical  men  to  represent  the  best  scientific  opinion.  By  an 
avoidance  of  statements  which  would  be  found  to  conflict  with 
subsequent  experience  in  the  world,  it  is  hoped  that  the  im- 


iv  PREFACE. 

pression  produced  upon  readers  may  remain  permanent.  A 
farther  discussion  of  the  subject  is  found  in  an  Appendix, 
containing  selections  from  some  of  the  best  recent  authorities, 
occupying  a  non-partisan  position. 

Nearly  the  whole  of  the  work  has  been  carefully  examined 
by  the  following  gentlemen,  to  whom  the  author's  most  sincere 
thanks  are  due:  Henry  P.  Walcott,  M.D.,  President  of  the 
Massachusetts  State  Board  of  Health;  Charles  P.  Polsom, 
M.D. ;  James  J.  Putnam,  M.D. ;  Thomas  Dwight,  M.D. ;  E. 
Wigglesworth,  M.D.;  C.  J.  Blake,  M.D. ;  Kobert  Willard, 
M.D. ;  and  W.  H.  Rollins,  M.D.,  several  of  whom  are  mem- 
bers of  the  Faculty  of  the  Harvard  Medical  School.  Thanks 
are  also  due  to  Mr.  A.  Lovell  for  careful  examination  of  man- 
uscript and  proofs. 


CONTENTS. 


CHAPTER 

I.   The  Tissues  and  Fluids  op  the  Body 


n.  The  Bones  and  Joints     . 

III.  The  Muscles      .... 

IV.  Circulation  and  Respiration 
V.  Food,  Drink,  and  Digestion   . 

VI.  The  Skin,  Clothing,  and  Bathing 

VII.  Voice.  —  Colds  . 

VIII.  The  Nervous  System 

IX.  The  Eye     . 

X.  The  Ear     . 

XI.  The  Teeth 

Xn.  Stimulants  and  Narcotics 


page 
1 

6 

29 

46 

77 

108 

122 

130 

151 

162 

167 

175 


APPENDIX  I.    Quotations  from  Medical  Authors 
APPENDIX  II.    Dissection  of  Animals  . 
APPENDIX  III.    Treatment  op  the  Drowned 


187 
195 
197 


PHYSIOLOGY. 

CHAPTER  I. 

THE  TISSUES  AND  FLUIDS  OP  THE  BODY. 

The  skin  of  our  bodies  is  in  some  respects  like  the  thin  sheet 
rubber  which  makes  a  toy  balloon.  Both  are  thin,  elastic, 
supple,  and  water-proof.  But  in  one  important  respect  they 
are  very  unlike.  The  skin  of  tlie  body,  if  examined  with  a 
microscope,  is  found  to  have  a  structure.  It  is  composed  of  an 
immense  number  of  small  objects  of  various  shapes,  fitted 
together,  entirely  unlike  anything  which  would  be  supposed 
from  the  external  appearance.  Rubber  has  no  such  internal 
structure ;  it  is  alike  in  all  parts. 

The  minute  objects  composing  the  skin  (and  other  parts 
also)  are  chiefly  cells  Mid  Jibres.  They  are  too  small  to  be  seen 
with  the  naked  eye.  Their  appearance  under  the  microscope 
is  shown  in  many  of  the  figures  of  the  chapters  following. 

Fibres.  —  Erom  cotton  or  woollen  thread  we  can  easily  pick 
out  the  fine  "  fibres  "  which  form  the  threads.  This  gives  a 
fair  idea  of  what  the  word  means.  A  somewhat  better  idea 
can  be  got  by  examining  the  coarse,  shaggy  sides  of  rough 
hides,  which  show  the  fibrous  structure  of  skin. 

Cells.  —  The  meaning  of  the  word  "  cell "  can  be  quite  well 
understood  by  examining  the  structure  of  a  honeycomb.  A 
large  part  of  our  bodies  is  composed  of  cells,  each  of  which  has 
its  wall  and  its  soft  contents.  In  addition,  cells  usually  have 
a  small  body  in  their  interior,  called  a  nucleus.     There  is  no 

1 


Z  PHYSIOLOGY. 

single  shape  for  cells,  as  there  is  in  a  honeycomb ;  they  are 
globular,  cylindrical,  flat,  or  long  like  threads. 

Tissues.  — The  word  "tissue''  is  often  applied  to  fabrics  of 
silk,  cotton,  and  other  material.  In  the  case  of  the  body,  it 
signifies  the  fabrics  or  substances  that  are  formed  by  joining 
and  interweaving  the  cells  and  fibres. 

Fibrous  Tissue  is  a  mass  of  fibres  interlaced  like  felt.  Some 
fibres  are  elastic  ;  others  are  not.  Fibrous  tissue  gives  strength 
and  firmness,  combined  with  elasticity  where  required.  It  forms 
a  casing  for  some  organs,  as  the  brain  and  the  heart ;  it  forms 
an  envelope  for  each  muscle  ;  it  wraps  and  ties  together  the 
joints  ;  all  the  "cords''  or  sinews  are  made  of  it. 

Epithelial  Tissue  is  composed  of  cells  of  various  forms 
]3acked  closely  together.  It  forms  the  outer  layer  of  the  skin ; 
it  also  forms  a  lining  for  the  mouth,  throat,  and  many  other 
internal  parts. 

Fatty  Tissue  contains  numerous  roundish  cells  filled  with 
fat ;  between  the  cells  there  are  meshes  or  bundles  of  fibrous 
tissue. 

Bony  Tissue  (represented  in  Pigs.  1  and  2,  pp.  6,  7)  is  pecul- 
iar in  having  its  substance  mostly  filled  somewhat  solidly 
with  mineral  matter ;  it  has,  however,  numerous  little  cavities, 
with  passages  connecting  them. 

Muscular  and  nervous  tissue  is  described  later. 

The  structure  of  plants  is  in  many  ways  like  that  of  living 
creatures.  They  contain  cells  and  fibres  in  abundance,  and  of 
many  sha]3es  and  sorts.  The  human  body  has  in  reality  a  kind 
of  life  like  that  of  a  plant ;  but  it  has  much  more  besides. 

Membranes.  —  The  general  meaning  of  this  word  is  a  thin, 
skin-like  structure ;  thus,  there  is  a  membrane  on  the  inside  of 
an  egg-shell.  In  the  body  there  is  a  variety  of  "  membranes," 
composed  of  cells  and  fibres  ;  they  may  be  considered  as  a  sort 
of  skin,  serving  to  line  the  cavities  and  passages  in  the  inte- 
rior of  the  body.  The  most  important  one  is  the  mucous  mem- 
brane, which  lines  the  mouth,  nose,  inner  ear,  eye,  throat,  air- 
passages,  stomach,  and  intestines. 


THE  TISSUES  AND   FLUIDS   OF  THE  BODY.  3 

The  fibrous  envelopes  of  the  brain  and  heart  are  also  called 
membranes.     The  "drum"  of  the  ear  is  a  membrane. 

FLUIDS. 

The  human  body,  like  that  of  animals  m  general  and  most 
plants,  contains  a  good  deal  of  water.  If  it  were  possible  to 
evaporate  from  a  person's  body  all  the  water  it  contains,  it 
would  lose  three-fourths  of  its  weight. 

But  water  is  not  found  pure  in  the  body  ;  it  always  contains 
some  animal  and  mineral  substances  dissolved  in  it  or  mixed 
with  it.  In  connection  with  many  different  substances,  and  in 
various  proportions,  it  forms  a  great  variety  of  fluids,  some  of 
which  are  the  blood,  the  lymph,  the  bile,  gastric  juice,  saliva, 
tears,  sweat. 

One  of  the  best-known  fluids  is  the  blood.  This  will  be 
described  in  another  chapter.  We  will  notice  here,  however, 
that  the  blood,  though  it  seems  to  be  everywhere,  does  not  fill 
the  body  as  water  fills  a  spoDge ;  it  is  all  contained  in  large 
and  small  tubes,  called  blood-vessels. 

In  the  parts  outside  of  these  blood-vessels  there  is  every- 
where found  a  clear,  colorless  fluid,  called  lymph.  The  body 
in  general  is  kept  moist  and  soft  by  the  presence  of  this  fluid. 

There  are  certain  other  fluids,  which  are  different  from  the 
blood  or  the  lymph  in  one  respect,  —  they  are  poured  out  upon 
the  surface  of  the  body  or  into  the  cavities  of  the  mouth,  stom- 
ach, etc.  Among  these  are  the  sweat  and  the  saliva.  These 
fluids  proceed  from  certain  small  openings,  which  lead  from 
little  bag-shaped  cavities,  called  glands. 

In  the  diagram  (Fig.  50)  of  the  skin,  the  sweat-glands  are 
shown.  This  kind  is  one  of  the  simplest,  consisting  of  a  single 
long  tube,  straight  in  one  part  and  curled  in  another.  Some 
kinds  of  glands  have  branches ;  these  may  be  so  numerous, 
wdth  rounded  ends,  as  to  resemble  bunches  of  currants  or 
grapes. 

Glands  of  every  sort  are  surrounded  by  coils  of  small 
blood-vessels.      From  the   blood  in  these    tubes    some  water 


4  PHYSIOLOGY. 

passes  through  into  the  cavity  of  the  gland,  and  with  the  water 
go  certain  other  things,  as  common  salt  (which  can  be  tasted  in 
tears  and  perspiration).  A  gland  has  the  power  of  choosing 
for  itself  which  of  the  many  chemical  substances  in  the  blood 
shall  come  to  it,  and  thus  each  sort  of  gland  manufactures  its 
own  special  sort  of  fluid. 

In  speaking  of  the  surface  of  the  body,  we  usually  mean  the 
skin.  But  the  body  has  interior  surfaces  also.  The  surface 
of  the  mouth  is  covered  with  mucous  membrane,  which  is 
kept  moist  by  the  saliva,  and  by  mucus,  produced  from  glands 
situated  in  different  parts  near  the  mouth.  One  of  them,  the 
parot'id  gland,  is  in  front  of  the  ear  and  is  the  part  which 
swells  in  mumps. 

The  interior  of  the  stomach  has  its  surface,  as  the  inside  of 
the  mouth  has,  upon  which,  when  food  is  present,  the  gastric 
glands  pour  out  the  gastric  juice  to  aid  in  digestion.  The 
pancreas  is  a  large  gland,  and  the  liver  is  one  much  larger 
still,  both  of  which  discharge  their  fluids  (pancreatic  juice, 
bile)  into  the  intestine  a  little  beyond  the  stomach,  to  continue 
the  work  of  digestion. 

The  kidneys  are  important  glands  which  pour  forth  certain 
harmful  substances,  freeing  the  body  from  their  presence.  In 
this  respect,  the  skin  is  like  the  kidneys,  for  the  perspiration 
contains  some  materials  which  would  be  injurious  if  kept  in 
the  system. 

Secretion  is  the  name  given  to  the  formation  of  these  vari- 
ous fluids  by  glands. 

Excretion  is  secretion  for  the  purpose  of  getting  rid  of  a  sub- 
stance for  which  the  body  has  no  further  use. 

SYNOPSIS. 

The  skin  and  other  parts  of  the  body  are  composed  of  vast  numbers 
of  minute  objects,  chiefly  ceUs  and  fibres.  Substances  like  the  gum 
called  rubber  have  none  of  this  structure. 

Fibres  are  like  threads ;  cells  are  small  sacs  of  different  shapes,  filled 
with  various  contents  and  containing  nuclei. 


THE  TISSUES  AND  FLUIDS   OF  THE  BODY.  5 

Fibres  and  cells  are  built  or  woven  into  tissues.  Fibrous  tissue  is 
firm.  Epithelial  tissue  consists  ot  layers  of  cells,  often  forming  a  skin 
or  lining.  Other  forms  are  fatty,  bony,  muscular,  and  nervous  tissue. 
Plants  have  many  similar  tissues. 

Membranes  are  skin-like  structures  of  cells  and  fibres.  The  mucous 
membrane  is  the  chief  one. 

Fluids.  —  Three-fourths  of  the  human  body  is  water.  Mixed  with 
various  substances,  this  forms  many  kinds  of  fluid, — blood,  lymph, 
and  the  secreted  fluids. 

Secretions  are  fluids  poured  out  from  sac-shaped  cavities  called 
glands.  Among  the  chief  are  the  sweat,  saliva,  gastric  juice,  pancre- 
atic juice,  bile,  urine. 

NOTE   TO   TEACHERS. 

The  very  brief  statement  of  general  facts  here  given  is  placed,  for 
certain  reasons,  at  the  beginning  of  the  book.  It  may,  however,  be 
thought  judicious  to  omit  it  until  perhaps  two  or  three  of  the  follow- 
ing chapters  have  been  studied.  A  beginning  can  very  properly  be 
made  at  the  subject  of  Bones. 

In  studying  the  subject  of  microscopic  structure,  some  pains  ought 
to  be  taken  that  the  scholars  understand  what  is  really  meant. 

The  cells  of  many  plant-structures  furnish  a  very  convenient  means 
of  giving  the  pupil  a  more  real  and  vivid  notion  of  what  the  word 
"  cell "  means  than  description  can  give.  A  common  pocket  lens  will 
show  with  perfect  clearness  the  large  cells  of  the  pith  of  annual  plants 
or  the  stalks  of  celery  or  those  of  the  young,  soft  leaves  or  shoots  of 
water-plants.  A  slice  cut  thin  with  a  sharp  knife  should  be  laid 
between  two  bits  of  glass  for  examination.  For  showing  cells  of  the 
animal  body  a  compound  microscope  is  required. 


SUGGESTED   QUESTIONS. 

Substances  with,  and  those  without,  structm-e.  Elements  or 
components  of  structure.  Fibres,  cells;  shape,  contents,  tissues. 
Fibrous,  epithelial,  bony,  fatty,  tissues.  Plant-structure,  membrane; 
examples. 

Water  in  body.  Fluids  of  body.  Blood,  lymph,  sweat,  tears, 
glands ;  form,  action ;  examples,  and  uses.     Secretion,  excretion. 


CHAPTER   II. 

THE  BONES   AND   JOINTS. 

BONES. 

Structure  and  Appearance  of  Bone.  — A  piece  of  fresh  bone 
that  has  not  been  cooked  is  usually  white  on  the  surface,  but 
if  held  up  to  the  light  it  shows  a  red  color  internally.-^     If  cut 


Fig.  1.  —  Bone  structure.  A  portion  taken  from  the  shaft  of  a  thigh  bone,  cut 
lengthwise,  magnified  200  diameters.  In  it  are  seen  several  canals,  or  pass- 
ages for  blood-vessels.  The  small,  black  objects  resembling  insects  are 
cavities  containing  cells,  which  communicate  with  each  other,  and  with  the 
canals,  by  means  of  many  minute,  thread-like  passages.  The  nourishmg 
fluids  circulate  through  these  passages  and  cells. 

1  Owing  to  the  blood  it  contains. 


THE   BONES  AND    JOINTS.  7 

across,  it  appears  reel.     When  prepared  for  a  skeleton,  it  is 
nearly  white. 

The  surface  is  mostly  smooth  and  hard,  like  ivory ;  the  parts 
beneath  are  spongy  or  porous,  with  many  fine  cavities  and 
little  thread-like  passages  for  the  blood-vessels.     Many  bones 


Fig.  2.  —  The  same,  cut  crosswise.  Four  canals  are  seen  cut  across ;  one  of 
them  communicates  with  a  canal  cut  lengthwise.  The  minute  passages  and 
cavities  are  more  distinct  than  in  Fig.  1. 


have  a  hollow  in  the  interior  j  this,  in  the  long  bones,  is 
filled  with,  a  yellow,  lardy  substance,  called  marrow.  A  sub- 
stance called  the  red  marrow  is  found  in  the  minute  pores  and 
cells. 

Composition  of  Bone.  —  The  bones  are  not  lifeless  parts,  like 
the  hair  and  nails.  They  are  as  truly  alive  as  any  other  part 
of  the  body.     Their  life  is  maintained  by  the  blood  which  cir- 


8 


PHYSIOLOGY. 


culates  through,  them  in  millions  of  very  small  tubes,  bringing 
nourishment,  as  it  brings  it  to  the  rest  of  the  body. 

The  life  of  a  bone  depends  very  much  on  a  certain  outer 
coat,  called  the  periosteum,  which  clings  closely  to  its  surface ; 


i 


Fig.  3.  — The  left  thigh  bone,  seen 
from  behind.  5,  head ;  6,  place  for 
attachment  of  round  ligament;  7, 
neck;  8,  greater  trochanter;  10, 
lesser  trochanter;  11  and  12,  smooth 
surf  aces  forming  part  of  knee-joint. 


WM 


Fig.  4.  —  The  same,  cut  lengthwise. 
1-1,  hollow  containing  marrow  ;  2- 
2,  showing  the  thickness  of  bone  at 
the  part  called  the  shaft;  3,  4, 
spongy  structure. 


if  this  coat  or  membrane  is  torn  off  by  accident  at  any  part, 

the  portion  of  bone  from  which  it  is  stripped  begins  to  perish. 

During  life,  therefore,  bone  is  covered  with  periosteum,  and 

contains  in  its  pores  blood-vessels,  blood,  and  the  fatty  mate- 


THE  BONES  AND  JOINTS. 


rial,  called  marrow.  When  all  these  are  removed,  we  have 
remaining  the  substance,  property  called  bone.  Yet  even  this 
is  not  a  simple  substance,  but  consists  of  two  entirely  differ- 
ent ones,  intermingled  with  each  other,  one  of  which  is  of  an 
animal  nature  and  easily  decays  (gelatin),  while  the  other  is 
mineral  (phosphate  of  lime,  carbonate 
of  lime,  and  other  ingredients).  The 
animal  and  the  mineral  parts  are  so 
mixed  as  to  seem  like  one  substance. 

It  is  easy  to  dissolve  out  the  min- 
eral components.  For  this  purpose, 
immerse  a  bone,  with  the  surface 
cleanly  scraped,  in  muriatic  acid 
diluted  with  water.  In  a  few  days 
the  bone  will  lose  its  brittleness,  and 
can  then  be  bent,  or,  if  its  shape  per- 
mits, can  even  be  tied  in  a  knot.^ 

The  animal  part  can  be  extracted 
from  a  bone  by  boiling  under  a  high 
steam-pressure  5  or  can  be  burned  out 
by  fire.  In  the  latter  case  what  is 
left  is  called  bone-ashes. 

The  form  of  the  bone  remains  the 
same  after  each  of  these  experiments. 

Besides  the  gelatin  which  is  dis- 
tributed through  the  bones,  there  is 
a  similar  substance,   called  cartilage 

or  c/ristle,  which  covers  the  ends    of    Fig.o.  — Thigh  bone  of 
'^  .  .  Pieces  2,  3,  4,  are  at 

bones.    It  is  a  tough,  elastic  material, 

easily  cut,  but  incapable  of  breaking. 
In    very   young   infants,    the   bones 

consist  chiefly  of  cartilage.  The  bony  material  is  depos- 
ited in  the  cartilage,  day  by  day  and  year  by  year,  and  it  is 
not  until  about  the  twentieth  year  of  life  that  the  bones  be- 

1  Two  ounces  of  the  strong  "commercial"  acid  may  be  mixed  with  a  pint 
of  water.    On  taking  the  bone  out,  wash  it  before  handling. 


child, 
attached 
to  shaft  (1-1),  by  cartilage 
only ;  fully  united  in  18th 
year  ;  5,  in  20tb  year. 


10  PHYSIOLOGY. 

come  fully  hardened.  Indeed,  tlie  process  continues  through 
life ;  and  in  middle  age  the  front  part  of  the  ribs  (which  till 
then  consist  of  cartilage)  begins  to  turn  to  bone.  By  placing 
the  hands  on  the  sides,  over  the  lower  ribs,  and  pressing 
firmly  inwards,  it  is  easy  for  a  young  person  to  feel  the  elas- 
ticity of  the  cartilaginous  parts. 

Properties  and  Uses.  —  The  bones  have  three  principal  uses. 

1.  As  a  covering  and  protection  to  some  parts  which  are  not 
directly  attached  to  bone.  The  brain  is  completely  covered 
by  the  skull ;  the  heart  and  lungs  are  shielded  by  the  chest- 
bones  ;  the  eye  lies  in  a  deep,  round  cavity  of  the  skull. 

2.  As  supporters  of  the  weight  of  the  body.  The  leg-bones, 
for  instance,  often  have  to  sustain  one  or  two  hundred 
pounds,  or  even  more;  besides  receiving  heavy  shocks  in 
jumping. 

3.  As  levers  for  moving  the  parts  of  the  body.  For  this 
purpose,  the  muscles  are  attached  to  them.  Almost  all  the 
movements  of  the  body  are  produced  in  this  way. 

If  is  evident  that  strength  is  one  of  the  first  qualities  re- 
quired of  a  bone.  In  securing  this,  the  material  has  been  used 
economically  and  skilfully.  The  bones  of  the  legs,  for  instance, 
are  made  hollow,  as  architects  make  iron  columns  hollow,  be- 
cause that  is  a  stronger  form  than  a  solid  column  of  the  same 
weight  would  be.  But  at  the  point  where  the  thigh-bone  bends 
at  an  angle  (i.e.  the  neck  of  the  bone)  there  is  especial  danger 
of  breaking;  there,  consequently,  the  interior  of  the  bone  is 
curiously  strengthened  by  cross-pieces  or  braces  adapted  to 
prevent  this  accident  (see  Fig.  4).  All  the  "long  bones" 
are  hollow  for  similar  reasons,  and  many  other  bones  are  soft 
and  spongy  in  the  middle;  but  all  have  their  greatest  hard- 
ness at  the  outside,  where  it  is  most  needed. 

Bones  also  require  to  be  elastic,  for  resisting  blows  or  sud- 
den shocks  in  falling  or  leaping.  This  property  of  elasticity  is 
due  to  the  gelatin  which  they  contain.  The  bones  of  children 
contain  less  mineral  matter  than  those  of  adults;  children,, 
therefore,  seldom  break  a  bone  in  their  frequent  falls.     The 


THE  BONES  AND  JOINTS. 


11 


bones  of  very  old  people  are  in  exactly  the  opposite  state,  and 
are  very  brittle  and  easily  broken. 

Form.  —  The  shapes  of  bones  differ  exceedingly.     Each  one 
has  its  own  proportions  and  outlines,  depending  on  the  use  it 


Fig.  6.  —  Skull  of  adult,  of  the  white  race.  The  zigzag  line  running  down  from 
the  summit  is  the  suture  which  joins  the  frontal  (forehead)  bone  to  the 
pari'etal  bone  behind.  Behind,  near  the  base,  another  suture  joins  the 
pari'etal  to  the  occip'ital  bone.  The  tem'poral  bone  (temple)  lies  behind  and 
above  the  opening  of  the  ear.  The  hinge  of  the  jaw  is  close  to  the  ear,  in 
front.  The  temple  is  seen  to  be  a  depressed  space :  this  in  life  is  filled  with 
a  strong  muscle. 

is  intended  for.  We  may  divide  bones  into  three  classes,  —  the 
long,  the  Jlat,  and  the  irregular.  It  is  evident  that  the  arm  and 
the  leg  require  long  bones.  That  of  the  thigh  is  the  longest 
in  the  body,  and  is  about  one-fourth  of  the  person's  height. 


12 


PHYSIOLOGY. 


The  hands  and  feet  also  require  bones  which  are  long  in  pro- 
portion to  their  thickness.  The  ribs  are  the  longest  of  any, 
proportionally  to  their  size.  Of  the  flat 
bones,  the  shoulder-blades  and  the  bones 
of  the  surface  of  the  skull  are  the  best 
known.  Those  of  the  face,  the  base  of 
the  skull,  the  wrist,  ankle,  and  spine  are 
irregular. 

THE    SKELETON. 

The  skeleton,  or  framework,  of  the  body, 
is  composed  of  bones  supplemented  (as 
above  mentioned)  by  cartilages,  and  bound 
together  by  tough  white  fibres  resembling 
sinew. 

A  simple  way  of  regarding  it  is  to  con- 
sider it  divided  into  the  bones  of  the  head, 
of  the  trunk,  and  of  the  limbs. 

Head.  —  The  bones  of  the  skull  are  com- 
plicated and  irregular.  Those  forming  the 
vaulted  part  may  be  seen  to  be  divided 
off  into  sections  by  zigzag  lines,  where  the 
bones  join  by  dovetailing  their  edges.  The 
union  is  so  fine  that  the  whole  practically 
forms  one  bone.  The  lines  resemble  a  sort 
of  rough  seam ;  hence  they  are  called 
su'tures  (from  the  Latin  sutu'ra,  a  seam). 
(See  Mg.  6.) 

The  arched  form  of  the  skull  gives  it 
greater  strength,  and  enables  it  to  bear 
heavy  weights  and  resist  blows.     There  are 


Fig.  7.  —Vertebral  column,  seen  from  the  right  side.  The  bodies  are  repre- 
sented separated  by  spaces,  which  in  life  are  occupied  by  cartilaginous 
cushions.  The  spinous  processes  project  behind ;  the  transverse  processes 
project  towards  the  observer,  at  points  near  the  bodies.  Openings  for  the 
exit  of  nerves  are  seen  near  the  transverse  processes.  The  curves  of  the 
spine  should  be  noticed. 


THE  BONES  AND  JOINTS. 


u 


twenty-eight  bones  in  the  skull,  of  which  eight  belong  to  the 
head  part,  fourteen  to  the  face,  and  six  very  small  ones  are 
found  in  the  ears. 

Trunk.  —  The  bones  of  the  trunk  comprise  the  spine,  and 
those  of  the  two  important  cavities  called  the  cJiest  and  the 
2'>elvis. 

The  spine  (also  called  back-bone,  vertebral  column,  spinal 
column)  is  formed  of  twenty-four  irregular  bones,  called  ver'- 
tebrce,  resting  one  on  the  other  so 
as  to  form  a  column.  The  long  line 
of  knobs  at  the  middle  of  a  per- 
son's back  is  not  the  main  body  of 
the  spine,  but  consists  of  the  tips 
of  certain  bony  projections,  extend- 
ing from  the  bodies,  or  more  solid 
central  portions,  of  the  vertebrae. 
The  bodies  are  thick  pieces  of  bone, 
resting  squarely  one  on  another. 
Between  the  single  pieces  there 
comes  a  firm,  thick  packing  of 
elastic  material.  The  joinings  of 
the  bodies,  therefore,  though  very 
firm,  are  not  rigid,  but  allow  a 
little  bending  in  different  direc- 
tions.    (See  Mg.  7.) 

A  ring   of  bone  projects  behind 
from  the   body   of    each  vertebra. 
The    twenty -four    rings    together 
form  a  sort  of  tube  (the  "spinal  canal "),  in  which  the  spinal 
cord  lies. 

Other  projecting  pieces  extend  sideways  and  backward,  and 
are  so  jointed  together  as  to  give  firmness  combined  with 
flexibility.  None  extend  from  the  front,  but  at  the  sides  there 
are  twelve  pairs  of  ribs,  jointed  to  the  bodies  of  twelve  ver- 
tebrae, which  curve  forward  around  the  chest.  They  are  joined 
in  front  to  the  breast-bone,  except  the  two  lowest  pairs,  which 


Fig.  8.  —  Bones  of  right  hand, 
seen  iu  front.  Wrist  bones 
above.  10-10,  metacarpus; 
11-11,  first  joints  of  fingers ; 
12-12,  second  joints;  ia-13, 
third  joints ;  14:  and  15,  joints 
of  thumb. 


14  PHYSIOLOGY. 

are  called  the  floating  ribs  and  are  free  at  the  front  ©nd.  The 
ribs,  with  the  back-bone,  form  a  sort  of  basket,  widest  below, 
but  open  both  at  top  and  bottom,  called  the  thorax,  or  chest. 
The  chest  contains  the  heart  and  lungs. 

There  are  seven  vertebrse  in  the  neck,  and  five  in  the  lower 
part  of  the  trunk,  which  have  no  ribs  attached  to  them.  The 
lower  are  much  larger  and  stronger  than  the  upper  ones. 

The  five  lower  vertebrse  form  a  backing  to  the  part  of  the 
trunk  called  the  abdo'men.  They  rest  on  a  strong  structure 
called  the  pelvis  (Latin  for  basin).  The  pelvis  is  com- 
posed of  a  middle  piece,  the  saxirum,  which  is  a  continuation 
of  the  vertebral  column,  and  two  side-pieces  (the  innom'inate 


Fig.  9.  —  Bones  of  right  foot,  from  inner  side.  1,  os  calcis  (heel) ;  5,  joint  sur- 
face of  astragalus ;  10,  scaphoid  ;  13,  greater  cuneiform ;  17,  lesser  cuneiform ; 
19,  20,  first  and  second  metatarsal  hones;  23,  first  phalanx  of  great  toe; 
24,  second  phalanx  of  great  toe ;  25,  second  and  third  phalanges  of  the  other 
four  toes. 


bones),  which  curve  around  and  meet  in  front,  forming  a  ring 
of  bone.  The  pelvis  is  the  lowest  part  of  the  trunk-skeleton. 
It  is  so  shaped  as  to  give  some  support  to  the  abdomen.  The 
side  of  the  pelvis,  where  it  is  felt  projecting,  is  the  hip. 
The  hip-joint  connects  the  thigh-bone  to  the  pelvis. 

Limbs.  —  The  arm  resembles  the  leg  in  many  ways.  Each 
consists  of  a  single  upper  long  bone,  two  long  bones  below, 
eight  bones  at  the  wrist,  corresponding  to  seven  in  the  ankle, 
with  nineteen  in  each  hand  and  foot.  The  knee-pan  does  not 
correspond  to  any  bone  in  the  arm ;  it  makes  the  number  equal 
in  arm  and  leg. 

The  four  limbs  are  attached  to  the  trunk  by  ball-and-socket 


THE  BONES  AND  JOINTS.  16 

joints.  They  are  not  connected  directly  with  the  spine,  but 
with  certain  side-structures,  which,  in  the  case  of  the  arms, 
consist  of  the  two  collar-bones  and  the  two  shoulder-Uades. 

The  collar-bone  is  slender  and  curved,  and  is  easily  traced 
at  the  lower  boundary  of  the  neck.  Its  inner  end  joins  the 
breast-bone,  its  outer  end  meets  the  shoulder-blade.  Taken 
together  these  form  the  shoulder-girdle.  The  shoulder-joint  is 
at  their  point  of  junction.  The  shoulder-blade  is  not  jointed 
to  any  bone  behind ;  by  moving  forward,  it  alloAvs  the  arms  to 
be  thrust  forward  or  raised. 

The  pelvis  has  already  been  described  as  a  part  of  the  trunk, 
but  a  more  scientific  statement  would  be  that,  while  the 
sacrum  belongs  to  the  spine,  the  two  large,  irregular  bones 
which  join  the  sides  of  the  sacrum  are  analogous  to  those  of 
the  shoulder-girdle.  They  form  the  pelvic  girdle,  to  which  the 
leg  is  jointed. 

JOINTS. 

Some  bones  are  joined  in  a  fixed,  immovable  way,  while 
others  can  be  moved  more  or  less  at  the  point  of  juncture. 

The  sutures  of  the  skull  afford  an  example  of  immovable 
joining.  In  infancy,  the  flat  bones  forming  the  roof  and  sides 
of  the  skull  are  soft  and  flexible,  being  composed  of  cartilage, 
except  a  small  patch  of  bone  in  the  middle  of  each ;  they  do 
not  even  meet  each  other  at  the  edges.  As  growth  proceeds, 
the  bones  first  touch,  then  interlock  by  a  great  number  of  fine 
dovetailings ;  the  central  patches  of  bone  also  spread  until  the 
whole  is  hard  and  solidly  joined  together.  In  advanced  life 
the  sutures  may  become  obliteraited  by  the  continued  develop- 
ment of  bone. 

Another  example  is  furnished  by  the  three  distinct  bones 
which  form  the  pelvis — the  sacrum,  and  the  right  and  left 
innom^inate  bones — united  closely  and  immovably,  though  not 
with  sutures. 

These  immovable  joinings  of  the  skull  and  pelvis  are  not 
joints  in  the  strict  sense.     A  true  joint  is  a  connection  between 


16 


PBYSIOLOGY. 


bones  which  allows  them  to  glide  over  each  other  at  the  points 

where  they  touch. 

The   sacrum,   on  which  the   spinal  column  rests,   forms  a 

sort  of  continuation 
of  the  latter,  and 
originally  consists 
of  several  distinct 
vertebrae,  which  at 
a  later  time  become 
one  structure.  The 
coccyx,  which  occu- 
pies the  place  pf  a 
tail  in  the  skeleton, 
is  placed  at  the 
lower  end  of  the 
sacrum,  and  in  adult 
or  advanced  life  is 
often  united  with  it. 
Each  innominate 
bone  consists,  in 
infancy,  of  three 
bones,  which  in 
adult  life  are  united 
so  closely  as  to  ap- 
pear one. 

The  structure  of 
a  joint  presents  the 
following   features  : 

1.  A  thin  layer  of  cartilage  covering  each  end  of  the  bones 
that  are  to  be  joined.  This  gives  a  perfect  fit  and  a  smooth- 
gliding  surface. 

2.  A  lubricating  fluid,  in  quantity  only  sufB.cient  to  keep  the 
surfaces  of  cartilage  perfectly  slippery,  so  as  to  make  motion 
easy  and  prevent  the  ends  of  the  bones  from  wearing  against 
each  other.  This  is  called  synovial  fluid.  It  resembles  the 
white  of  an  Qgg  in  appearance. 


Fig.  10.  —  Ligaments  of  right  wrist,  front  view. 


THE  BONES  AND  JOINTS. 


17 


3.  The  edges  of  the  bones  are  fitted  with  a  ring  of  strong 
material  called  the  capsule,  which  holds  the  bones  together,  and 
prevents  the  fluid  from  escaping. 

4.  Additional  strength  is  given  by  other  bands  of  fibrous 
tissue  called  ligaments. 


Fig.  11.  —  Ligaments  of  right  hip,  seeu  in  front.    1,  cut  tendon  of  great  musde 
of  front  of  thigh,  turned  up;  3,  6, 11.  great  fan-shaped  expansion  of  ligament 
21,  lesser  trochanter;   22,  projection  of  the  hip  bone,  which  can  he  felt  a 
short  distance  above  the  joint. 

The  capsule  and  ligament  are  composed  of  a  white  material, 
which  is  the  same  that  is  seen  in  the  white,  stringy,  tough 
parts  of  meat,   or  in  the  sinews.      It  is   exceedingly  strong. 


18 


PHYSIOLOGY. 


but  not  elastic.  It  is  used  in  many  places  to  fasten  bones 
together ;  sometimes  immovably,  at  other  times  loosely,  in  the 
manner  of  a  joint.     It  is  a  necessary  part  of  joints,  and  is  em- 


FiG.  12.— Section  through  pelvis  and  hip-joint,  seen  in  front.  1,  sacrum; 
2,  ilium ;  5,  6,  7,  8,  9,  ligaments;  10,  cup-shaped  cavity  for  head  of  thigh-bone ; 
11,  rim  of  cartilage;  12,  round  ligament;  14-14,  cavity  of  the  joint,  with 
capsule  enclosing  it. 

ployed  in  making  the  synovial  sacs.  The  name  of  this  sub- 
stance is  white  fibrous  tissue.  It  has  many  other  uses  besides 
those  described  here.  Every  muscle  is  covered  with  a  thin, 
transparent  sheet  of  it,  and  is  fastened  to  the  bone  by  a 
thicker  portion,  often  resembling  a  cord. 

In  "limber-jointed"  persons  the  ligaments  joining  the  bones 
are  looser,  and  do  not  set  the  bones  so  firmly  together  as  is  the 


THE  BONES  AND  JOINTS.  19 

case' in  other  persons.  The  joints  are  most  flexible  in  youth. 
By  beginning  in  childhood,  some  persons  are  trained  to  bend 
their  limbs  and  back  in  extraordinary  ways,  and  become  the 
contortionists  or  india-rubber  men  of  circuses. 

There  are  four  kinds  of  joints, — the  ball-and-^ocJcet,  the 
hinge,  the  pivot,  and  the  gliding. 

The  ball-and-socket  joint  is  that  which  permits  the  greatest 
freedom  of  movement ;  it  is  employed  to  connect  the  limbs  to 
the  body. 

The  hip-joint  displays  this  structure  better  than  any  other. 
There  is,  in  the  hip-bone,  a  cup-shaped  cavity,  into  which  the 
rounded  head  of  the  thigh-bone  fits,  turning  freely,  and  allow- 
ing the  bone  to  move  in  all  directions.  Both  the  cup  and  the 
head  of  the  bone  are  covered  with  smooth  cartilage,  making 
them  fit  each  other  closely.  The  synovial  fluid  is  kept  in  its 
place  by  a  sac  or  capsule,  which  encloses  the  whole  joint,  and 
is  very  flexible,  but  very  strong  and  tough.  Its  shape  is  some- 
what like  that  of  a  cuff  or  wrister,  the  upper  edge  of  which  is 
attached  around  the  edge  of  the  cup,  and  the  lower  edge  around 
the  bone.  This  arrangement  makes  an  air-tight  joint.  The 
hip-bone  is  kept  in  place  chiefly  by  the  force  of  atmospheric 
pressure,  or  what  is  commonly  called  suction. 

There  are  other  means,  however,  for  keeping  it  in  place ; 
such  are,  the  capsule  itself,  which  is  quite  strong ;  also,  a  cer- 
tain ligament  or  cord  inside  of  the  capsule  (the  "  round  liga- 
ment"), which  ties  the  head  of  the  bone  to  the  bottom  of  the 
cup,  and  prevents  the  bone  from  turning  around  too  far  while 
revolving.  The  joint  is  further  wrapped  in  ligaments  outside 
of  the  capsule,  as  seen  in  Fig.  11.  The  great  muscles  of 
the  parts,  also,  are  constantly  drawing  the  thigh  and  hip 
together. 

The  arm  is  joined  to  the  shoulder-blade  by  an  arrangement 
somewhat  like  the  hip-joint,  but  the  cup  is  very  shallow.  A 
part  of  the  shoulder-blade  curves  around  over  the  head  of  the 
arm-bone,  forming  the  point  of  the  shoulder ;  it  serves  to  pro- 
tect the  joint,  and  helps  to  keep  the  arm  in  its  socket.     The 


20 


PHYSIOLOGY. 


movements  of  the  arm  are  much,  freer  than  those  of  the  hip, 
which  is,  of  course,  a  convenience ;  but  at  the  same  time  the 
arm  is  much  more  frequently  forced  out  of  its  socket,  or 
"  dislocated,'^  than  the  hip. 

Hinge-joints  are  such  as  move  in  one  definite  direction,  and 
back  again,  like  a  pocket-ruler,  —  mathematically  speaking,  in 
one  plane.  Among  the  chief  are  those  of  the  knee,  the  elbow, 
the  fingers,  and  the  toes.  The  jaws  move  by  hinge-joints, 
which  have,  however,  less  fixity,  and  permit  motion  sideways, 
such  as  is  required  in  chewing.  The  joints  between  the  fingers 
and  hand  are  hinged,  but  by  laying  the  hand  flat  on  a  table 


Fig.  13.  —  Hip-joint,  opened  by  cutting  the  capsule  circularly.  1,  capsule; 
3,  ring  of  cartilage;  7,  8,  round  ligament ;  11, head  of  bone ;  13, neck ;  14,  cap- 
sule, cut  edge;  16,  greater  trochanter ;  18,  lesser  trochanter. 

there  is  seen  to  be  considerable  side-play.      The  wrists  and 
ankle  are  a  sort  of  irregular  hinge-joints. 

Certain  processes  or  projections  of  bone  may  be  seen  in  the 
skeleton  at  the  elbow,  in  front  and  behind,  which  prevent 
motion  beyond  a  certain  point.  Ordinary  door-hinges  have  a 
similar  contrivance. 


THE  BONES  AND  JOINTS. 


21 


A  pivot-joint  is  seen  in  the  connection  of  the  radius  with 
the  humerus  at  the  elbow.  This  pivot  action  can  be  seen  and 
felt  in  a  thin  arm,  by  resting  the  elbow  on  a  table,  and  letting 
the  hand  turn  as  in  using  a  gimlet.  By  placing  the  fingers 
against  the  person's  elbow, 
as  it  rests  on  the  table, 
it  will  be  seen  that  the 
hinge  part  may  remain 
unmoved  while  the  pivot 
is  revolving. 

Another  pivot  is  used 
to  enable  the  skull  to 
rotate  upon  the  top  of  the 
spinal  column.  Its  con- 
struction can  be  seen 
better  than  described. 

The  gliding  -  joint  is 
found  between  the  small 
Dones  of  the  wrist  and 
ankle,  where  there  is  but 
little  motion. 

The  spinal  column  is 
capable  of  considerable 
bending  in  all  directions. 
The  twenty-four  pieces  of 
which  it  is  composed  are 
not  jointed  together  in 
any  of  the  above  ways ; 
they  are  connected  by  a 
series  of  cushions,  which 
also    serve    the    purpose 

of  ligaments.  The  joining  of  two  vertebrae  might  be  imi- 
tated by  cementing  two  blocks  of  wood  together  with  a 
sheet  of  hard  rubber,  which  would  hold  the  blocks  firmly 
together,  and  admit  of  a  little  motion.  By  means  of  twenty- 
two  such  joinings  the  spine  as  a  whole  is  enabled  to  bend  a 


Fig.  14.  —  Right  arm.  A,  with  palm  shown ; 
B,  with  back  of  hand  shown  ;  H,  humerus ; 
R,  radius ;  U,  ulna. 


22  PHYSIOLOGY. 

good  deal.  There  are,  however,  true  joints  between  the  first 
and  second  vertebrse,  also  between  the  skull  and  the  spinal 
column. 

Remarks  on  the  Skeleton.  —  The  skeleton,  taken  together,  is 
an  absolutely  necessary  part  of  our  organism.  If  a  person 
could  be  deprived  of  his  bones  and  cartilages,  he  would  become 
a  mass  of  soft  material,  incapable  of  moving,  and  even  of 
breathing,  and  would  perish  in  a  few  minutes. 

There  have  been  persons  whose  joints  have  been  so  stiffened 
by  disease,  that  they  practically  do  i^ot  exist.  Such  persons 
can  still  eat,  digest,  breathe,  and  speak,  but  they  have  little 
more  power  of  motion  than  if  they  were  statues.  All  our 
movements  (except  those  of  the  internal  soft  organs)  are  due 
to  the  action  of  muscles  upon  joints. 

Some  animals,  however,  are  so  constructed  as  to  be  capable 
of  life  without  possessing  any  hard  parts  corresponding  to  a 
skeleton.     Such  are  slugs  (snails  without  shells)  and  jelly-fish. 

Many  animals  have  their  skeletons  outside  in  the  form  of  a 
shell  or  crust,  like  lobsters. 

There  is  a  very  large  class  of  animals,  of  widely  different 
forms  and  habits,  which  possess  skeletons  that  are  essentially 
^  like  that  of  man.  They  all  have  a  back-bone,  with  a  skull,  ribs, 
and  (in  many  cases)  upper  and  lower  limbs.  The  name  of 
this  class  is  the  Vertebrates.  It  comprises,  first,  those  which, 
like  the  human  race,  have  the  power  of  giving  suck  to 
their  young  —  the  mammalia ;  then  the  birds,  the  reptiles,  and 
(lowest  of  all)  ihejlshes. 

HYGIENE  OF  THE  BONES  AND  JOINTS. 

The  word  "hygiene"  means  the  science  of  health.  It  teaches 
how  to  make  and  keep  ourselves  w^U  and  strong,  and  to  avoid 
disease. 

The  care  of  the  bones  should  begin  in  infancy.  An  infant's 
bones  are  at  first  soft  and  weak.  In  order  that  they  may  grow 
firm  and  solid,  its  food  must  contain  lime  and  phosphorus  (see 


THE  BONES  AND  JOINTS.  23 

page  9).  Milk  contains  these  substances  in  a  fit  proportion, 
and  is  therefore  suitable  for  young  children. 

A  well-fed  child  may  be  compared  to  wheat  growing  in  a 
good  soil,  and  sucking  up  from  it  the  lime,  phosphorus,  and 
many  other  things  which  it  requires. 

Rickets  is  a  disease  in  which  the  bones  do  not  become  firm 
as  soon  as  they  ought ;  the  children's  leg-bones,  for  instance, 
may  become  bent  (bow-legs,  knock-knees),  or  the  chest  may 
grow  out  of  shape  (pigeon-breast).  Scrofula  often  affects  the 
joints.  Both  diseases  are  largely  caused  by  poor  food,  and 
want  of  fresh  air  and  sunlight,  in  childhood.  They  may  be 
inherited  from  unhealthy  parents. 

Eheumatism  is  often  due  to  cold  and  dampness.  It  can, 
therefore,  to  some  extent  be  prevented. 

Little  children  in  school  often  have  to  sit  on  seats  that  are 
too  high  for  them,  so  that  their  feet  do  not  reach  the  floor.  All 
persons  need  a  firm  support  for  the  feet  while  sitting;  the 
want  of  it  is  not  only  most  uncomfortable,  but  may  cause  de- 
formity of  the  leg  in  the  young. 

Twisted  spine  (spinal  curvature)  is  very  common  among 
young  persons  who  do  not  take  enough  exercise;  it  is  ex- 
plained further  under  "  Muscles." 

Fracture  means  a  breaking.  A  bone  can  be  broken  by  a 
blow  or  fall,  as  a  stick  of  wood  can.  The  same  power  that 
made  it  and  caused  it  to  grow  supplies  the  means  by  which  the 
broken  ends  of  a  bone  can  grow  together,  if  they  are  kept  in 
place.  The  surgeon's  duty  after  "  setting ''  the  bone  (putting 
it  in  place)  consists  simply  in  arranging  the  bandages  so  that 
the  healing  shall  go  on  quietly,  undisturbed  by  movements. 
Whoever  happens  to  have  charge  of  a  person  with  a  broken 
limb  before  a  surgeon  arrives  should  be  most  careful  to  pre- 
vent unnecessary  movements  of  the  broken  parts. 

A  sprain  is  a  wrench  received  by  a  joint,  in  which  some  of 
the  fibres  of  the  joint  are  more  or  less  torn.  It  is  excessively 
painful,  and  often  requires  as  long  time  for  recovery  as  a 
broken  limb- 


24  PHYSIOLOGY. 


EFFECTS  OF  ALCOHOLIC  DRINKS. 

If  the  parents  are  drunken,  the  child  will  often  be  born 
weakly,  with  a  tendency  to  scrofula  or  rickets. 

Spirituous  drinks  of  all  sorts,  unless  used  as  medicines, 
should  be  forbidden  to  children,  as  being  most  injurious,  and 
liable  to  make  them  permanently  feeble. 

The  bones  do  not,  on  the  whole,  show  the  bad  effects  of 
these  drinks  very  much. 

Gout,  however,  is  a  disease  of  adults,  which  is  due  to  excess 
in  "good  living"  (that  is,  "high  living"),  meaning  a  super- 
abundance of  animal  food,  with  a  free  use  of  alcoholic  drinks. 
It  is  very  painful,  lasts  many  years,  and  causes  deformity  of 
the  joints. 

SYNOPSIS. 

Description.  —  The  color  of  prepared  bone  is  white  ;  of  unprepared, 
red  inside  and  white  outside.  The  surface  is  smooth,  interior  spongy 
or  porous.  Many  bones  are  hollow.  Their  cavities  are  filled  with 
marrow.  They  are  nourished  by  great  numbers  of  blood-vessels. 
The  outer  coat  (  periosteum)  is  essential  to  the  life  of  a  bone. 

Composition.  —  Bone  is  composed  of  an  animal  substance  (gelatin) 
intimately  combined  with  mineral  substances  (phosphates  and  carbo- 
nates of  lime,  etc.).  When  the  latter  are  removed  by  acid,  the  bone 
becomes  flexible ;  when  the  gelatin  is  removed  by  boiling  or  burning, 
it  becomes  brittle,  without  losing  its  form. 

Cartilage,  a  tough,  elastic  material,  covers  the  ends  of  bones;  in 
infants  it  forms  the  chief  component  of  the  whole  bone,  and  complete 
hardening  by  deposit  of  mineral  salts  does  not  occur  till  about  the  age 
of  twenty  years ;  in  later  life  the  hardening  becomes  excessive.  The 
ribs  of  young  persons  are  very  elastic. 

Uses  of  Bones.  —  They  hold  the  soft  parts  in  place  and  give  shape 
to  the  body.  They  protect  internal  parts.  They  support  the  weight. 
They  form  levers  to  move  the  body.  Bones  are  made  strong  and 
hard  on  the  outside,  while  inside,  where  strength  is  not  required,  they 
are  spongy  or  hollow.  They  are  elastic,  from  the  presence  of  animal 
matter ;  most  so  in  children,  while  in  old  persons  they  become  very 
brittle. 


THE  BONES  AND  JOINTS.  25 

Forms.  —  Very  various.  May  be  divided  into  long,  flat,  and  irreg- 
ular. The  longest  is  the  thigh-bone.  The  limbs  and  thorax  contain 
many  long  bones.  The  shoulder-blade  and  some  of  the  skull-bones 
are  flat. 

The  Skeleton  or  framework  of  the  body  is  composed  of  bones  and 
cartilages  bound  together  by  tough  white  fibres.  It  may  be  divided 
into  three  regions,  —  head,  trunk,  and  limbs. 

The  Head.  —  The  bones  of  the  head  are  very  irregular.  Those  of 
the  skull  are  dovetailed,  looking  as  if  joined  by  seams  (sutures)  ;  their 
arched  shape  imparts  strength.  There  are  eight  bones  in  the  skull, 
fourteen  in  the  face,  and  six  very  small  ones  in  the  ears. 

The  Trunk  includes  the  spine,  with  thorax  and  pelvis.  The  spine 
comprises  twenty-four  vertebrae  arranged  like  a  column.  Their  pro- 
jecting spinous  processes  can  be  felt  as  a  line  of  knobs  in  the  back. 
The  main  part  of  a  vertebra  (its  body)  is  a  thick,  flat,  round  bone, 
separated  from  the  corresponding  parts  of  the  next  vertebrae  by  a 
firm,  thick,  elastic  packing.  A  ring  of  bone  projects  backward  from 
each  body;  the  twenty-four  rings  form  the  spinal  canal.  The  thorax 
includes  the  ribs  and  breast-bone.  The  pelvis  is  composed  of  the 
sacrum  and  two  haunch-bones  (the  ossa  innominata). 

The  Limbs. — The  number  of  bones  is  equal  in  an  arm  and  a 
leg.  The  arms  are  joined  to  the  trunk  by  the  shoulder-girdle  (collar- 
bones and  shoulder-blades)  ;  the  legs,  by  the  pelvic  girdle  (or 
pelvis) . 

The  Joints.  —  Bones  are  united  either  fixedly  or  by  joints.  The 
sutures  are  immovable  joinings.  The  sacrum,  and  ossa  innominata, 
are  each  composed  of  several,  which  are  united  by  growth.  A  joint 
contains  cartilage,  synovial  fluid,  a  capsule,  and  ligaments.  Capsules 
are  composed  of  white  fibrous  tissue,  tough  like  sinews. 

There  are  four  classes  of  joints.  The  hip  and  shoulder  exhibit  the 
ball-and-socket  principle  well.  The  hinge  is  shown  in  many  joints 
of  the  limbs.  The  pivot-joint  acts  at  the  elbow,  associated  with 
a  hinge-joint.  Gliding- joints  occur  at  the  wrist  and  ankle.  The 
vertebrae  are  united  by  cushions  rather  than  joints. 

The  skeleton  is  essential  to  our  life.  Most  of  our  motions  are  made 
by  its  aid,  combined  with  muscles.  Some  animals  have  no  bones  ; 
some  have  an  external  skeleton  ;  the  highest  animals  (vertebrates) 
possess  a  skeleton  which  is  much  like  that  of  man,  especially  in  the 
fact  that  it  contains  a  back-bone. 

Hygiene.  —  The  bones  of  infants  and  children  require  to  be  built 


26  PHYSIOLOGY. 

up  with  phosphorus  and  lime,  which  must  be  present  in  the  food. 
Rickets  is  a  disease  in  which  the  bones  are  soft  through  defective 
nutrition.  Scrofula  often  attacks  joints.  Improperly  shaped  seats 
may  cause  deformities.  Fractures  are  repaired  by  the  processes  of 
nature,  if  kept  at  rest.  Sprains  are  often  as  serious  as  fractures. 
Alcoholic  Drinks.  —  See  the  text. 


SUGGESTIONS   FOR   QUESTIONING   THE   PUPIL. 

It  has  been  thought  best  to  avoid  the  formality  and  constraint  of 
printed  questions.  In  what  follows,  the  teacher  will  find  that  the 
statements  of  the  text  are  referred  to,  or  pointed  out,  by  the  use  of 
single  words  or  short  phrases  adapted  to  form  the  basis  of  the  exam- 
ination. It  will  not  be  difficult  to  build  upon  these  a  variety  of  ques- 
tions which  will  test  the  pupil's  knowledge  more  thoroughly  than 
would  be  the  case  in  usmg  fixed  formulae.  For  instance :  if  speaking 
of  periosteum,  the  teacher  may  ask,  "  What  is  the  outer  coating  of 
bone  called?  and  what  is  its  use?"  or,  "What  is  periosteum?"  or, 
"What  structure  (or  membrane)  is  essential  to  the  life  of  a  bone?" 
etc. 

The  synopsis  of  the  chapter  is  adapted  to  call  to  mind  the  leading 
points  in  case  of  a  rapid  review.  It  may  also  be  found  useful  (at  the 
teacher's  option),  during  the  first  study  of  the  subject. 

Bone.  —  Color.  Surface.  Interior.  Structure.  Contents.  Peri- 
osteum. Composition.  Acids,  effect  of.  Boiling.  Cartilage.  In- 
fants' bones.  Uses  of  bones.  Strength.  Elasticity.  Forms ;  name 
examples. 

Skeleton;  divisions.  Bones  of  skull — character,  number,  arrange- 
ment, junctions;  form  of  skull.  Spine  —  number  of  vertebrae,  and 
their  three  divisions.  Vertebrae  —  body,  ring,  projections,  junctions. 
Bones  forming  the  thorax.  Abdomen.  Pelvis.  Sacrum.  Hip. 
Limbs — bones,  joints,  connections  with  trunk.  Shoulder -girdle. 
Pelvic  girdle. 

Joints.  —  Two  sorts  of  joinings.  Sutures  —  their  development. 
Pelvis  —  components  and  junctions.  Definition  of  true  joints.  Four 
features  of  the  structure  of  a  joint.  Capsule.  Ligaments.  Flexi- 
bility. Four  kinds  of  joints.  Hip-joint — cup,  capsule,  ligaments; 
how  strengthened.  Shoulder-joint  —  compare  with  hip.  Hinge- 
joints —  their  nature;  examples.  Comments  on  certain  ones.  Pivot- 
joints  at  elbow  and  base  of  skull.     Gliding-joints.     Junctions  of  ver- 


THE  BONES  AND  JOINTS.  27 

tebr?e.  Importance  of  the  skeleton.  Motion.  Animals  destitute  of 
skeleton ;  those  with  external  skeleton  ;  the  vertebrates. 

Hygiene  defined.  Infants'  bones.  Xutrition  of  bones.  Rickets. 
Scrofula.  Rheumatism.  Seats.  Curvature  of  spine.  Fractures. 
Sprains. 

Alcoholic  Drinks. 

NOTES    FOR   TEACHERS. 

In  all  parts  of  Physiology,  teachers  will  find  the  interest  very  much 
increased  by  the  actual  sight  of  the  objects  described.  This  is  espe- 
cially the  case  with  the  bones,  which  are  less  repulsive  to  beginners 
than  some  other  organs,  since  they  are  already  in  some  degree  familiar 
objects.  The  following  preparation  for  the  study  of  bones  is  sug- 
gested. 

1.  Obtain  from  a  butcher,  the  day  before  the  lesson,  a  part  of  one 
of  the  long  bones,  sawn  across,  with  the  marrow  in  it :  the  shin  of  an 
ox  is  very  suitable,  though  many  others  may  be  substituted.  Such 
fresh  portions  should  be  kept  moist  and  cool ;  e.g.  in  a  refrigerator,  or 
under  an  inverted  bowl,  or  wrapped  in  a  damp  cloth.  This  will  show 
the  solid  or  ivory-like  part,  the  hollow  structure  peculiar  to  long  bones, 
and  the  yelloio  marrow. 

2.  The  rib  of  a  sheep  or  other  small  animal ;  the  adhering  flesh 
should  be  removed  with  a  knife.  This  can  be  held  up  to  the  light  to 
show  that  the  interior  is  red;  its  ends  wiU  show  some  spongy  tissue, 
which  is  red ;  after  noting  these  points,  the  bone  may  be  broken  in 
two  and  its  interior  further  examined.  N"os.  1  and  2  should  be 
uncooked. 

3.  An  end  of  one  of  the  larger  bones,  as  the  thigh-bone,  of  almost 
any  animal,  sawn  in  two  lengthwise,  displays  the  spongy  tissue  to 
great  advantage.     Either  cooked  or  uncooked  will  do. 

4.  The  drumstick  and  other  convenient  parts  of  a  fowl  may  be 
saved,  and  after  standing  over  night  in  water  may  be  cleansed  of  the 
adhering  soft  parts,  and  dried.  There  is  an  instructive  resemblance 
between  many  of  these  bones  and  those  of  man ;  e.g.  the  "  second 
joint,"  or  thigh  ;  the  "  drumstick,"  or  tibia  and  fibula ;  and  also  the 
three  large  wing-bones,  —  the  humerus,  radius,  and  ulna. 

5.  Some  of  the  bones  of  fowls  ( or  larger  animals)  should  be  reserved 
with  the  periosteum  and  cartilage  attached.  They  are  easily  shown ; 
the  cartilage  can  be  cut  in  slices,  and  the  periosteum  stripped  off  in  a 


28  PHYSIOLOGY. 

sheet.     Tendons,  muscular  attachments,  smdjibrous  tissue  can  be  shown 
at  the  same  time. 

6.  The  leg  and  wing  of  boiled  fowls  supply  convenient  examples  of 
joints.  For  a  larger  specimen,  the  hock-joint  of  an  animal  illustrates 
the  hinge  principle  beautifully. 

7.  The  action  of  acid  on  a  bone  is  at  first  not  noticeable ;  but  in  the 
course  of  half  an  hour  or  less  bubbles  of  carbonic  acid  will  be  seen 
covering  its  surface.  (The  carbonate  of  lime,  from  which  this  gas 
proceeds,  forms  only  one-sixth  of  the  mineral  substance  of  bone ;  pure 
carbonate  of  lime,  in  marble  or  limestone,  effervesces  very  briskly  in 
the  same  acid,  and  may  interestingly  be  compared  with  the  bone.)  A 
rib  is  a  suitable  bone  for  this  experiment.  When  made  soft,  it  should 
be  soaked  in  water,  and  afterwards  preserved  in  alcohol. 

The  teacher  should,  if  possible,  give  some  time  to  inspecting  a  skele- 
ton before  trying  to  teach  its  mysteries  to  pupils.  A  complete  skele- 
ton ought  to  be  in  the  possession  of  every  large  cchool ;  but  even  a 
partial  one  is  of  great  service,  and  a  neighboring  physician  may  be 
able  to  lend  such  objects. 

Much  of  the  anatomy  of  bones  can  be  shown  upon  the  living  human 
body.  After  seeing  a  single  phalanx  (finger-bone),  or  the  correspond- 
ing bones  of  cattle,  no  one  can  find  difficulty  in  understanding  the 
form  and  arrangement  of  similar  bones  in  his  own  hand.  The  shape 
of  the  lower  jaw  is  easily  felt.  Such  protuberances  as  the  "funny- 
bone"  (olecranon),  and  the  greater  trochanter  (at  the  hip-joint),  and 
the  spinous  processes  of  the  back  are  readily  made  out.  Ribs  and 
collar-bones  are  usually  easy  to  trace. 

It  is  suggested  that  it  is  more  important,  as  well  as  more  interesting, 
to  know  the  uses  of  bones  than  to  be  able  to  give  their  names.  Partic- 
ular attention  should  (for  example)  be  given  to  the  manner  in  which 
the  skeleton  is  constructed  as  a  support,  —  with  arches  under  the  feet, 
an  arch  (pelvis)  at  the  basis  of  the  spine,  and  two  columns  supporting 
the  span  of  the  latter ;  the  rough  points  and  ridges,  with  the  attached 
fibres,  tendons,  and  flesh,  should  not  pass  unheeded ;  and,  as  far  as 
may  be,  ideas  should  be  formed  of  the  way  in  which  the  naked  skele- 
ton is  in  life  clothed  with  flesh,  and  where  the  internal  organs  are  sit- 
uated within  it. 

Teachers  wishing  to  carry  this  kind  of  instruction  farther  than  is 
here  indicated,  will  find  valuable  aid  in  Prof.  H.  P.  Bowditch's  little 
work,  "  Hints  for  Teachers  in  Physiology." 


CHAPTER   ITL 

THE  MUSCLES. 

The  muscles  are  the  organs  by  which  movements  of  the 
body,  or  of  parts  of  the  body,  are  produced.     They  are  of  two 


P'DORSAL... 
VERTECi, 


/         TUBERCaiUM 

sca_ful=^e: 


Fig.  15.  —  Principal  muscles  of  the  back. 


29 


30 


PHYSIOLOGY. 


sorts,  —  tlie  voluntary  and  the  involuntary.  The  former  are 
under  the  control  of  the  will;  they  are  more  easily  studied, 
and  will  be  chiefly  spoken  of  here. 


VOLUNTARY    MUSCLES. 

Nearly  all  the  muscles  of  this  class  lie  quite  near  the  sur- 
face of  the  body.  Together  with  the  bones,  they  compose 
almost  the  whole  of  the  limbs ;  they  form  a  layer  over  nearly 
the  whole  of  the  trunk ;  and  even  the  face  and  skull  have  many 
muscles.     In  thin  persons  their  outlines  can  often  be  seen 


Fig.  16. —  A  sinsfle  muscular  fibre  magnified  Fig.  17.  —  Muscular  fibre,  un- 

250  diameters.    The  torn  sheath  is  seen  at  broken.     The    sheath    pos- 

5,  5.     At  1,  1,  the  striae    (markings)  run  sesses  nuclei  at  3,  3,    The 

both  lengthwise  and    across;    at    2,    only  transverse    markings    only 

across ;  4,  is  a  fibril.  are  seen. 


under  the  skin.  In  most  persons  the  spaces  between  the  mus- 
cles are  somewhat  filled  up  with  fatty  tissue.  Fat  also  forms 
a  layer  beneath  the  skin,  veiling  the  form  of  the  muscles,  and 
giving  a  rounded  outline  to  the  body.  The  form  of  the  body, 
however,  in  general  depends  so  muoh  on  the  bones  and  mus- 


TBE  MUSCLES. 


31 


cles,  that  artists  study  them  in  order  to  draw  the  body  correctly 
(Fig.  15). 

The  muscle  itself  consists  of  a  mass  of  red  tissue,  which  in 
animals  is  known  as  flesh,  or  meat  (Figs.  16, 17).  INIuscles  are 
sometimes  attached  to  the  bone  directly ;  but  they  often  have, 


BRACHIALISl- 


PPQJMATOR  TERES    ^ 


PA'-MARIS   L01^JGUS 
fLEXOR  DIGITTCOMMSUBLIMIS    ^ 
FLE/OR  POLUCIS  LOMGUS 


FLEXOR  CARPI  RAD1AU5 


.JLELXOR  OIGG.COMM.  SU8UMIS 
FLEXOR  CARPtJJLNARlS 


Fig.  18.  —  Muscles  and  tendons  of  the  arm,  front  view. 


at  one  or  both  ends,  a  firm,  strong,  white  cord  called  the  tendon. 
In  many  cases,  tendons  are  quite  long ;  such  may  be  seen  about 
the  wrist  and  the  back  of  the  hand,  coming  clearly  into  sight 
when  motions  are  made  with  the  fingers.  Those  of  the  ankle 
are  still  more  conspicuous.  The  use  of  such  tendons  is  the 
same  as  that  of  a  rope  in  a  sailor's  hands ;  they  do  not  them- 
selves pull,  but  enable  the  muscles  to  give  a  pull  to  distant  parts. 


32 


PHYSIOLOGY. 


EXTENSOR 
CARPI    ULNARIS 


We  can  form  a  fair  idea  of  the  appearance  of  muscles  by 
examining  the  leg  of  a  fowl,  the  fleshy  part  of  which  is  com- 
posed of  the  "  bodies  "  or  soft  parts  of  the  muscles,  while  the 
stringy,  uneatable  parts  are  the  tendons.  A  frog's  leg  with 
the  skin  removed  gives  a  still  clearer  idea.  The  meat  of  ani- 
mals, birds,  and  fish  consists  of  muscle,  its  color  varying  from 

brown  to  red,  pink,  and 
white.  When  used  as 
food  it  may  be  called 
EXTENSOR  flesh -meat,  to  distin- 
RAD.ALis  guish  it  from  such  parts 
as  the  liver,  kidneys,  or 
sweetbread. 

Muscles  of  the  class 
here  described  ("volun- 
tary" muscles)  can  be 
seen  with  the  micro- 
scope to  consist  of  a 
great  number  of  fine 
fibres,  laid  side  by  side, 
each  fibre  being  cross- 
marked  by  numerous 
fine  lines  (Figs.  16,  17). 

PHYSIOLOGY. 

If  a  person  opens  and 

shuts  his  fist  vigorously, 

we  can  feel  the  muscles 

of    the    forearm   move 
Fig.  19.  —  Muscles  and  tendons  of    the  back    „^-u'i„    "u^    Ar^^a    if.     tp-q 
of  the  right  hand  and  lower  arm.  ^^^^®    ^®    ^^^^    ^^  '     ^^ 

can  also  see  the  action 

of  the  cords  at  the  wrist,  pulling  upon  the  hand.  By  using 
a  tape-measure,  we  can  prove  that  the  forearm  is  larger 
around  at  the  moment  when  the  fist  is  firmly  closed,  than 
when  it  is  allowed  to  remain  open  without  effort.  By  feel- 
ing, we  ascertain  that  the  muscle  not  only  swells,  but  becomes 


THE  MUSCLES. 


33 


harder  at  the  moment  of  effort.  Naturally  it  becomes  shortened 
at  the  same  time,  and  it  is  the  act  of  shortening  that  causes 
it  to  pull. 

By  laying  the  bare  arm  on  a  table  and  x:)erforming  slight 


LI6.  PATtUARE 


Fig.  20.  —  Muscles  of  the  knee,  leg,  and  toot. 

motions  with  the  fingers,  e.g.  that  of  gently  raising  them,  one 
at  a  time,  as  if  to  strike  the  keys  of  a  piano,  we  can  observe 
(both  by  sight  and  touch)  that  a  part  of  the  forearm  may  con- 
tract while  other  parts  are  at  rest.     This  illustrates  the  fact 


34 


PBYSIOLOGT. 


that   the   limb   contains    a   number   of   muscles   of    different 


uses. 


One  of  the  largest  tendons  of  the  body  is  found  above  the 
heel.  Those  of  the  front  of  the  ankle  are  very  easily  felt,  if, 
while  sitting,  we  raise  the  toe,  keeping  the  heel  on  the  floor. 


RAOIAl.  ARTERY.^ 

FLEXOR  poaiaa . 

FUCXOR  RADIALI9. 

FL  DlCaSUBU— 
MEDIAN  NERVE. 


MEDIAN. 
NERV/E 


EXOR  ULNAR 


Fig.  21.  —  Muscles,  arteries,  and  nerves  of  the  front  of  the  right  hand. 

Most  voluntary  muscles  are  attached  to  two  or  more  bones, 
and  when  they  act  they  pull  so  as  to  bring  the  bones  nearer 
together.  Por  example,  the  biceps  of  the  upper  arm  is  firmly 
attached  to  a  projecting  knob  of  bone  on  the  radius  (one  of 
the  bones  of  the  forearm);  its  upper  end  is  fastened  to  the 
shoulder-bones.     It  pulls  in  such  a  way  as  to  bring  these  two 


THE  MUSCLES. 


35 


parts  near  each  other,  and  in  doing  so,  the  hinge-joint  at  the 
elbow  is  bent. 

There  are,  however,  some  muscles  which  are  not  so  attached. 
The  mouth  is  surrounded  by  a  ring  of  muscle  situated  in  the 
lipS;  which  when  contracted  draws  or  "  purses  "  it  up ;  similar 
muscles  surround  the  eyes ;  they  are  called  the  orbicularis  of 
the  mouth,  and  the  orbicularis  of 


the 


eye, 


from    the    Latin   word 


meaning  "circular." 

For  every  motion  there  is  a 
counter  -  motion,  and  for  every 
muscle  there  is  another  called  its 
antagonist,  which  acts  in  the  op- 
posite direction.  The  muscles  of 
one  side  of  the  arm  bend  (flex) 
the  elbow,  wrist,  and  fingers  ;  their 
antagonists  of  the  other  side 
straighten  (extend)  them.  The 
same  is  true  of  the  knees.  For 
raising  the  arm  there  is  a  xoower- 
ful  muscle  (the  deltoid),  which 
covers  the  shoulder  like  a  cap ;  for 
lowering  the  arm  one  might  sup- 
pose no  muscle  was  needed,  since 
it  will  fall  of  its  own  weight,  but 
by  placing  the  hand  in  front  of  the 
armpit,  one  can  feel  the  contrac- 
tion of  a  powerful  muscle  (the 
pectoral)  when  the  hand  strikes  a 
quick  blow  downward.  At  the 
rear  border  of  the  armpit  a  similar  muscle  may  be  felt. 

The  back  possesses  a  great  quantity  of  muscle,  which  acts 
in  the  opposite  direction  to  that  of  the  front  part  of  the  trunk. 

The  action  of  a  muscle  involves  the  principle  of  the  lever. 
Levers  are  of  three  orders,  all  of  which  are  found  in  the  body. 
The  first  order  is  used  in  striking  with  the  fist,  or  a  weapon : 


Fig.  22. —The  three  orders  of 
levers  illustrated  in  the  arm. 
W  stands  for  weight;  F,  for 
fulcrum;  P,  for  power.  The 
arrow  shows  the  direction  of 
the  action. 


36  PHYSIOLOGY. 

the  second,  in  raising  the  body  on  the  parallel  bars  ;  the  third, 
in  pulling  or  lifting. 

The  first  order  is  also  represented  by  the  base  of  the  skull, 
which  is  supported  or  pivoted  on  the  back-bone,  and  can  be 
drawn  down  by  muscles  behind  or  in  front.  When  the  muscles 
at  the  back  of  the  neck  act,  the  chin  is  raised ;  when  those 
in  front  act,  the  head  is  bowed  forward. 

The  second  order  is  seen  at  the  heel.  The  weight  of  the 
body,  in  standing,  is  supported  on  the  ankle ;  if  the  person 
stand  on  his  toes,  he  has  to  raise  his  own  weight  an  inch  or 
two  from  the  ground,  which  is  done  by  a  pull  from  the  rear. 
In  the  diagram  the  elbow  acts  like  the  heel. 

PRINCIPAL   USES  OF  THE  VOLUNTARY   MUSCLES. 

1.  Locomotion  and  Work.  —  Locomotion  is  moving  from  one 
place  to  another.  It  includes  such  acts  as  walking,  creeping, 
swimming,  diving,  flying,  climbing,  running,  jumping ;  bring- 
ing into  play  most  or  all  of  the  voluntary  muscles  of  the  trunk 
and  limbs.  Work  includes  useful  acts,  such  as  lifting,  carry- 
ing, using  tools,  writing,  playing  musical  instruments,  and  the 
like. 

2.  Breathing.  —  Many  large  muscles  are  used  in  breathing ; 
they  will  be  described  elsewhere.  Their  work  is  immensely 
important,  since  life  and  speech  depend  on  them. 

3.  Speech.  —  The  voice  is  formed  by  the  action  of  the  chest, 
throat,  larynx,  mouth,  and  nose,  all  of  which  are  furnished 
with  muscles  that  have  the  power  of  changing  the  shape  of 
these  parts.  The  tongue  is  a  mass  of  muscle,  and  the  lips 
are  muscular.  Weakness  (from  disease,  cold,  hunger  or  thirst, 
paralysis,  etc.)  affects  the  power  of  these  muscles  and  there- 
fore changes  the  tone  of  the  voice. 

4.  Eye.  —  The  eyes  are  moved  in  their  sockets,  to  look  in 
the  directions  required,  by  several  little  muscles.  Paralysis 
from  disease  of  the  brain  affects  them ;  so  does  intoxication. 

'    5.  Ear.  —  The   movements  of    the   outer  ear  are   unimpor- 


THE  MUSCLES. 


37 


tant  in  man,  though,  prominent  in  lower  animals.  The  middle 
ear  (behind  the  drum)  contains  little  muscles  attached  to  the 
small  bones. 

6.  Expression.  —  Many  parts  of  the  face  are  provided  with 


Fig.  23.  — Muscles  of  expression.  1,  retrahens  aurem;  2,  attollens  aurem; 
3,  attrahens  aurem ;  4,  occipitalis ;  9,  frontalis ;  10.  pyramidalis  nasi ;  12,  or- 
bicularis palpebrarum  (closes  eyes) ;  15,  levator  labii  superioris  alaeque  nasi 
(raises  lip,  etc.);  16,  levator  latiii  superioris;  17,  18,  zygomatici;  19,  levator 
anguli  oris  (raises  corner  of  mouth)  ;  21,  compressor  naris ;  28,  31,  thin  mus- 
cles under  the  skin  of  the  neck:  32,  masseter  (chewing) ;  31,  sterno-mastoid 
(bowing) ;  35,  trapezius.    The  circular  fibres  around  the  mouth  close  it. 


38  PHYSIOLOGY. 

little  muscles  below  the  skin  wMcli  pull  the  face  in  different 
directions.  They  are  set  in  action  by  feelings  or  emotions. 
Some  draw  the  corners  of  the  mouth  up  in  smiling ;  some  draw 
them  down  in  sorrow ;  others  wrinkle  the  forehead  in  anger 
or  suspicion;  others  give  a  humorous  look  to  the  corners  of 
the  eye.  These  motions  are  usually  made  without  our  knowl- 
edge ;  they  are  then  spontaneous  or  involuntary.  But  we  can 
by  practice  learn  to  perform  them,  so  as  to  appear  to  feel  in 
various  ways,  as  actors  can  do ;  or  we  can  learn  to  check  them 
so  as  to  hide  our  real  feelings,  which  is  much  harder. 

The  classes  of  actions  thus  far  described  are  mostly  under 
the  control  of  the  will.  We  can  perform  them  when  we 
choose,  and  refrain  when  we  choose.  The  muscles  which  per- 
form them  are  called  "the  organs  of  the  will,"  and  are  the 
agents  by  which  one  class  of  persons  do  good  deeds,  and 
another  class  do  evil.  We  are  therefore  morally  and  relig- 
iously responsible  for  the  uses  to  which  we  put  these  muscles. 

INVOLUNTARY    MUSCLES. 

The  act  of  swallowing  begins  by  pushing  the  food  back  with 
the  tongue.  When  it  is  beyond  the  tongue,  the  muscles  of  the 
upper  throat  squeeze  it  into  the  gullet.  These  actions  are 
voluntary,  though  it  is  a  remarkable  fact  that  we  can  seldom 
perform  them  unless  we  have  something  in  the  mouth  to 
swallow. 

The  gullet  is  a  long  tube  reaching  to  the  stomach.  It  is 
lined  with  a  smooth  sort  of  skin,  somewhat  like  that  of  the 
inside  of  the  mouth  (mucous  membrane)  ;  it  has  also,  all  the 
way  down,  a  thin,  outer  layer  of  muscles  going  round  it  circu- 
larly, which  begin  to  contract  and  squeeze,  one  after  the  other, 
as  soon  as  anything  enters  the  upper  part  of  the  gullet.  Thus 
the  food  is  pushed  or  squeezed  down  into  the  stomach.  We 
do  not  feel  these  muscles  act,  and  we  cannot  make  them 
work  by  trying  to  do  so.  They  are  independent  of  the  will, 
or  involuntary. 


THE  MUSCLES. 


39 


The  same  sort  of  muscles  form  a  coating  over  the  stomach 
and  the  intestines,  and  cause  the  food,  once  swallowed,  to 
travel  slowly  onward. 

They  are  also  found  in  the  veins  and 
arteries. 

They  are  different  in  a^jpearance 
from  voluntary  muscles.  As  shown 
in  Mg.  24,  they  are  composed  of  very 
long  fibres,  tapering  at  the  ends;  a 
common  name  is  smooth,  or  unstriped, 
muscular  fibre.  The  fibres  of  vol- 
untary muscles  are  shown  by  the 
microscope  (Fig.  16)  to  be  marked 
by  a  very  great  number  of  cross- 
stripes.  The  heart  is  composed  of  the 
latter  sort,  though  it  is  not  controlled 
by  the  will. 


HYGIENE  OF  THE  MUSCLES. 


Fig.  24.  —  Involuntary  mus- 
cle. 1,  1,  nuclei  of  the 
fibres;  2,  3,  fibres;  4,  5, 
two  fibres  joined. 


One  of  the  most  remarkable  things 
about  muscle  is  the  way  it  increases 
by  being  used,  and  shrinks  when  not 
used.  If  a  broken  arm  is  put  \v^  in  splints  and  kept  immovable 
for  some  weeks,  it  will  be  found  at  the  end  of  that  time,  when 
the  splints  are  removed,  that  the  arm,  though  not  diseased,  is 
almost  paralyzed ;  the  owner  of  it  has  to  exercise  it  until  the 
power  of  moving  it  has  been  regained.  And  on  the  other 
hand,  we  all  know  how  readily  we  can  increase  both  the  power 
and  the  size  of  the  muscle  of  the  arm  by  using  dumb-bells. 

The  muscles  of  an  infant,  like  its  bones,  are  weak ;  yet  we 
see  that  it  is  constantly  moving  them,  opening  and  shutting 
its  fingers  and  toes,  moving  its  arms  and  legs  in  odd  ways. 
As  it  grows  older,  its  powers  increase;  it  first  creeps,  then, 
when  its  leg-bones  are  strong,  it  walks.  Later,  at  the  age  of 
three  or  four,  it  becomes  so  fond  of  running  that  a  grown 
person  who   should  try  to  keep  up  with  it  would  be  tired. 


40  PHYSIOLOGY. 

This  is  the  natural  way  for  children  to  grow  strong,  and  it  is 
wrong  to  prevent  them  from  having  the  opportunity. 

Eor  children  and  young  people,  certainly  up  to  the  age  of 
full  growth,  running  is  one  of  the  best  exercises,  and  all  who 
have  the  strength  should  play  running  games.  One  chief 
benefit  from  running  is  that  which  is  felt  by  the  lungs; 
"  the  wind  ^'  is  improved.  Another  consists  in  strengthening 
the  power  of  the  heart,  which  is  needed  in  order  to  make  the 
blood  flow  strongly  and  freely. 

A  child  needs  several  hours  of  play  daily ;  a  person  from 
fourteen  to  eighteen  had  better  have  two  hours  of  play  on  the 
feet,  or  of  walking,  each  day. 

"  Exercise  "  is  beneficial  in  several  ways  :  — 

1.  It  gives  a  good  appetite,  and  prevents  trouble  in  the 
stomach,  such  as  lazy  people  are  apt  to  suffer  from. 

2.  It  thus  enables  us  to  take  more  nourishment,  which  is 
very  useful  for  the  growing  body  of  a  child,  making  all  parts 
stronger  and  healthier. 

3.  It  promotes  good  humor  and  improves  the  power  of  study. 

4.  Properly  conducted  exercise,  by  strengthening  the  mus- 
cles of  the  back,  will  prevent  and  even  cure  the  disease  called 
lateral  {i.e.  sideways)  curvature  of  the  spine.  But  ordinary 
play,  however  useful  in  some  respects,  will  not  always  give  a 
person  a  "straight  back."  There  is  much  play  that  is  one- 
sided ;  for  example,  pitching  ball  with  one  hand,  which  some- 
times makes  a  boy's  body  grow  irregularly.  When  one 
shoulder  is  higher  than  the  other,  or  "grows  out,"  there  is 
danger  of  curved  spine.  A  great  many  girls  and  but  few  boys 
have  this  deformity ;  the  reason  of  this  difference  is  the  fact 
that  very  few  girls,  from  the  age  of  twelve  up,  take  the  exer- 
cise they  require,  while  most  boys  do  get  in  play  something 
like  what  they  need. 

5.  Exercise  ought  to  develop  the  chest.  Ordinary  play  does 
not  do  this  to  any  great  extent ;  it  strengthens  the  legs,  but 
leaves  the  arms,  back,  and  chest  comparatively  weak.  Climb- 
ing, swimming,  boxing,  rowing,  and  gymnastics  remedy  this. 


THE  MUSCLES.  41 

A.  good-sized  chest  is  one  of  the  most  important  things  for  a 
person  who  wishes  to  be  healthy.  Most  consumptive  people 
have  weak  and  small  chests,  and  many  a  person  might  pro- 
long his  life  by  training  himself  so  as  to  remedy  this  defect. 
But  weakly  persons  ought  to  take  the  advice  of  experienced 
physicians  or  trainers  before  beginning  exercise,  as  they  may 
otherwise  put  themselves  in  danger. 

6.  A  person  who  has  been  regularly  trained  in  bodily  exer- 
cises is  pretty  sure,  when  grown  up,  to  be  able  to  do  more 
work  in  his  profession  or  business  than  he  could  otherwise 
have  done.     He  becomes  stronger  "  all  round." 

7.  A  great  deal  of  vice  can  be  prevented  by  steady  habits 
of  vigorous  exercise  in  good  company. 

The  body  is  usually  strongest  and  most  able  to  take  exer- 
cise in  the  forenoon.  The  morning,  before  breakfast,  is  enjoyed 
by  some  for  walking  and  other  exercise,  but  many  cannot  exer- 
cise at  that  time  without  feeling  much  fatigue,  which  is  of  a 
weakening  sort. 

Exercise  does  us  most  good  when  it  makes  us  breathe  more 
quickly  and  fully  than  usual,  and  when  it  starts  the  perspira- 
tion. It  is  plain  that  during  exercise  no  tight  clothing  should 
be  worn ;  such  articles  are  not  only  uncomfortable,  but  even 
dangerous.  Especially  the  neck,  chest,  and  waist  must  be 
very  loosely  clad. 

Exercise  should,  as  a  rule,  leave  us  feeling  moderately 
fatigued.  It  is  unsafe  to  eat  a  meal  directly  after  making 
severe  exertion ;  the  stomach  is  capable  of  feeling  the  fatigue 
of  such  exertion,  and  if  food  is  then  taken  the  stomach  has  no 
power  to  digest  it,  and  severe  illness  may  follow.  Eest  before 
eating  is  proper  when  one  is  greatly  tired. 

After  a  hearty  meal,  very  little  exercise  should  be  taken  for 
some  time. 

It  is  much  better  to  exercise  in  the  open  air  when  possible, 
and  when  exercising  in  a  room  we  should  open  windows  more 
or  less. 

Excitement  of  mind  is  apt  to  set  the  muscles  in  motion ; 


42  PHYSIOLOGY, 

some  people,  even  in  ordinary  conversation,  feel  compelled  to 
make  motions  with  the  hands,  called  gestures,  — "  to  let  off 
steam,"  as  it  were.  This  is  more  natural  to  the  Italians  or 
French  than  to  us,  and  more  to  us  than  to  the  English.  In 
a  violent  passion  some  persons'  muscles  seem  to  run  away 
with  them;  the  arms  fly  about,  the  feet  stamp,  and  blows  or 
scratches  are  given  almost  unconsciously.  Such  men  are  like 
drivers  who  let  their  horses  "get  away  with  them."  The 
habit  of  getting  into  a  rage  is  very  hurtful  to  children;  it 
weakens  the  nerves,  and  tends  to  produce  the  dreadful  disease, 
epilepsy. 

STIMULANTS   AND   NARCOTICS. 

It  might  be  thought  that  a  "stimulant"  would  make  a  man's 
muscles  stronger  for  a  short  time,  but  this  is  not  so.  A  per- 
son who  can  lift  a  hundred  pounds  may  take  a  drink  of  spirit, 
wine,  or  beer,  and  in  a  few  minutes  he  may  feel  stronger  than 
before ;  but  he  will  not  be  able  to  lift  any  more,  in  reality. 

Before  a  boat-race,  or  a  foot-race,  or  a  prize-fight,  men  are 
"trained"  for  some  weeks  so  as  to  make  them  strong  and 
enduring.  They  run,  walk,  box,  use  gymnastics.  (If  their 
chests  are  small,  they  are  not  allowed  to  make  the  attempt.) 
They  rise  early,  go  to  bed  early,  eat  regularly  of  wholesome 
food;  and  if  they  have  been  accustomed  to  use  alcoholic 
drinks,  they  are  obliged  either  to  give  them  up  altogether,  or 
to  take  very  little.  Tobacco,  also,  is  either  given  up  by  men 
in  training,  or  is  used  in  small  amounts. 

Practical  experience,  therefore,  shows  that  alcoholic  drinks 
do  not  help  a  man  to  grow  strong.  Much  less  do  they  help  a 
boy. 

When  an  excess  is  taken,  the  muscles  become  partly  para- 
lyzed for  a  time.  People  show  this  in  various  ways.  Most 
will  "  talk  thick,"  owing  to  a  partial  paralysis  of  the  muscles 
of  the  tongue  and  mouth.  There  is  an  inability  to  control  the 
movements  of  the  eyes.     The  hand  is  unsteady.     The  legs  are 


THE  MUSCLES.  43 

weakened,  the  body  totters ;  and  in  complete  intoxication  the 
whole  person  is  "  as  limp  as  a  wet  rag."  Old  drinkers  are  apt 
to  have  trembling  hands. 

Tobacco,  taken  by  a  person  not  used  to  it,  makes  him  feel 
utterly  weak  and  prostrate.  Boys  who  become  accustomed 
to  it  are  often  sluggish,  and  show  a  lack  of  desire  for  play 
and  exercise,  which  is  most  unnatural  and  unwholesome.  A 
healthy  boy  wants  to  be  much  on  the  move,  and  anything 
which  makes  him  feel  otherwise  is  contrary  to  the  right  prin- 
ciples of  his  bodily  nature. 

Tea,  coffee,  cocoa,  which  are  so  useful  in  many  cases,  are  cap- 
able, when  used  by  certain  persons,  of  causing  the  muscles  to 
twitch  or  tremble.  This  is  more  common  with  people  who 
take  no  exercise.  Such  effects  are  signs  that  the  system 
is  being  slowly  poisoned. 

SYXOPSIS. 

Voluntary  Muscles  lie  near  the  surface,  and  form  the  chief  part  of 
the  limbs.  Their  outlines  form  a  large  part  of  the  outlines  of  the  body. 
They  are  usually  attached  to  bones,  and  by  pulling  on  the  bones  cause 
the  movements  of  the  body.  The  muscular  tissue  is  the  substance 
caUed  meat.  Its  fibres  are  marked  with  fine  cross-lines.  Muscles 
usually  end  in  cords  or  tendons,  which  attach  them  to  bones. 

The  muscles  are  enabled  to  give  a  puh  by  the  change  of  shape  which 
they  undergo,  —  swelling  in  the  transverse  dhection  and  shortening 
in  the  longitudinal.  They  grow  harder  at  the  same  time.  Some 
muscles  are  not  attached  to  bone:  that  which  forms  a  ring  around 
the  mouth  is  an  instance. 

Each  muscle  has  an  antagonist,  which  moves  the  joint  or  limb  in  an 
opposite  direction.     Examples  are  seen  in  the  limbs. 

The  three  orders  of  levers  are  represented  in  the  body  by  the  dif- 
ferent arrangement  of  the  muscles  in  connection  with  the  jomts. 

The  voluntary  muscles  are  the  means  of  performing  a  great  variety 
of  actions,  including  locomotion  or  movement  from  place  to  place, 
useful  labor,  breathing,  speech ;  they  assist  in  sight  and  hearing ;  they 
cause  the  face  to  take  various  expressions. 

Involuntary   Muscles   are   of   a   different   appearance   from   the 


44  PHYSIOLOGY, 

former  class.  The  fibres  (except  in  the  heart)  have  no  cross-markings. 
They  act  upon  the  parts  which  receive  and  digest  food,  beginning  at 
the  point  where  tlie  food  enters  the  throat.  Swallowing  is  a  voluntary- 
act  only  at  its  beginning.  They  are  also  found  in  the  veins  and 
arteries. 

Muscles  grow  larger  by  being  much  used,  and  shrink  when  disused. 
They  are  very  weak  in  infants,  and  develop  very  gradually  by  very 
frequent  motion  and  by  play.  Exercise  is  useful  in  several  ways : 
it  increases  appetite,  makes  the  stomach  healthy,  increases  the  amount 
of  food  consumed,  promotes  good  humor,  clears  the  mental  powers ;  it 
prevents  deformities,  if  properly  regulated ;  it  develops  the  size  of  the 
chest,  improves  the  wind,  and  strengthens  the  power  of  the  heart,  so 
that  a  person  is  better  able  to  do  vigorous  athletic  work ;  it  tends  also 
to  prevent  chest  disease ;  it  gives  a  power  to  do  more  work  in  busi- 
ness ;  it  tends  to  prevent  vice. 

Exercise  should  not  be  taken  at  times  when  the  body  is  weak  or 
tired ;  not  much  of  it  just  before  or  after  eating.  It  should  be  taken 
in  pure  air. 

Alcoholic  drinks  do  'not  increase  muscular  power.  They  are  not 
useful  to  persons  who  are  training  themselves  for  athletic  contests. 

An  excess  of  alcoholic  drink  causes  partial  paralysis  of  the  muscles, 
and  in  some  oases  leads  to  trembling  of  the  muscles. 

Tobacco  makes  some  persons  sluggish  and  disinclined  to  take 
exercise. 

Tea,  coffee,  cocoa,  may  cause  twitching  of  the  muscles. 


SUGGESTED   QUESTION'S. 

Two  classes  of  muscles.  Voluntary  muscles,  where  found.  Out- 
lines of  the  body.  Action  of  muscles  on  the  bones.  Tendons  : 
appearance;  use;  examples.  Muscles:  general  appearance;  micro- 
scopic appearance ;  color  ;  examples. 

Contraction  of  the  muscles;  experimental  illustrations.  Separate 
muscles  in  arm.  Examples  of  tendons.  Muscles  unattached  to  bone. 
Antagonism ;  examples.     Levers  :  three  orders ;  examples. 

Uses  of  muscles.  Locomotion  and  work;  breathing;  speech, 
organs  of,  weakness  of;  sight;  hearing  ;  expression  of  feeling.  Moral 
responsibility. 

Involuntary  muscles;  appearance.     Swallowing,  mixture  of  volun- 


THE  MUSCLES.  45 

tary  and  involuntary  acts.  Coating  of  the  digestive  tract ;  use. 
Blood-vessels. 

Effect  of  use  and  disuse.  Splints.  Infants.  Play,  llunning.  Uses 
of  exercise:  digestion;  nourishment;  mental  state;  form  of  the 
body,  chest,  heart,  lungs ;  general  powers ;  good  habits.  Points 
connected  with  exercise :  time ;  clothing ;  amount  of  exertion ; 
meals ;    rest ;    air.      Excitement. 

Stimulants:  effect  on  muscular  exercise ;  in  fatigue  and  chilliness; 
in  training.     Paralysis.     Tremor. 

Tobacco.     Tea  and  similar  drinks. 


NOTES   FOR  TEACHEPvS. 

It  may  not  seem  desirable  to  exhibit /oo(i  before  a  class  as  an  object 
of  anatomical  study.  It  is  well  to  know  that  very  interesting  views 
of  muscles  can  be  had  by  simply  removing  the  skin  from  the  body  of 
any  bird  which  may  have  been  shot  as  injurious  to  the  crops  or  as  a 
nuisance.  The  feathers  of  the  breast  being  parted,  a  single  cut  (care- 
fully directed)  with  a  pointed  knife  along  the  middle  line  of  front  of 
the  body  is  nearly  all  that  need  be  done  with  instruments.  The  skin 
can  be  removed  with  the  fingers  very  easily.  The  pectorals  are  re- 
markably large  and  dark  colored  in  flying  birds,  though  white  in 
chickens.  The  muscles  of  the  arm  (wing)  and  leg  are  easily  exposed, 
and  present  considerable  general  resemblance  to  those  of  the  human 
body.  By  pulling  on  the  pectorals  and  on  certain  arm-muscles,  several 
movements  of  the  wings  and  feathers  can  be  imitated. 

The  resemblance  of  a  frog's  leg  to  that  of  the  human  subject  is 
closer  than  in  the  case  of  a  bird. 

In  neither  case  is  any  dissection,  properly  speaking,  requii'ed  to 
give  a  general  view  of  muscles. 


CHAPTER   IV. 

OIEOULATIOJJ  Am  EESPIEATIOlf. 

THE  BLOOD. 

This  substance,  which  is  estima,te(i  to  compose  one-thir- 
teenth of  the  human  body,  by  weight,  is  a  mixture  of  different 
substances, — serum,  which  is  a  fluid;  fibrin^  which  is  fluid  in 
the  body,  but  solidifies  when  the  blood  is  taken  from  the  body ; 
and  with  these  two,  which  are  fluid  in  our  systems,  there  is 
mingled  an  immense  number  of  minute  blood-cor'pusdes,  or 
blood-cells,  of  two  kinds. 

Blood  freshly  drawn  from  an  animal  and  set  aside  in  a  glass 
vessel  soon  becomes  a  red,  jelly-like  mass.  This  change  is 
called  coagulation. 

If  we  let  the  coagulated  blood  stand,  it  gradually  separates 
into  two  parts,  —  a  light,  yellow  liquid,  consisting  of  serum  col- 
ored by  a  few  blood-cells,  and  a  compact,  semi-solid  mass,  the 
clot,  which  contains  the  solidified  fibrin  with  the  great  part  of 
the  blood-ceUs.  The  clot  is  red ;  darker  below  and  lighter  at 
top. 

The  blood  is  the  nourisher  of  the  body;  and  its  different 
parts  are  each  nutritious.  The  serum  contains  a  considerable 
amount  of  albu'min  (see  "Food").  The  fibrin  and  the  blood- 
cells  closely  resemble  the  material  which  composes  flesh,  or 
muscle.  Besides  these,  blood  contains  such  mineral  substances 
as  are  found  in  the  body.  Blood  is,  in  fact,  composed  of  nearly 
the  same  ingredients  as  milk,  though  in  different  proportions. 
It  is  so  nearly  like  muscle  in  its  chemical  composition,  that  a 
distinguished  French  physiologist  named  it  "  liquid  flesh.'' 
46 


CIBCULATION  AND   llESPIBATION. 


47 


Certain  other  substances  exist  in  the  blood,  which  may  be 
called  the  waste-products  of  the  system,  or  materials  which 
come  from  the  using-up  of  the  tissues  of  the  body.  The  same 
liquid,  therefore,  which  carries  food  to  the  parts,  also  takes 
off  the  waste  or  sewage  matters  from  the  parts.  These  mat- 
ters are  chiefly  carried  to  the  sweat-glands,  to  the  kidneys, 
and  to  the  lungs,  each  of  which  excretes  (or  sends  off)  waste- 
matter  mixed  with  large  quantities  of  water. 


Fig.  25.— Redaud  white  corpuscles  of  the  blood,  magnified.  A,  moderately 
magnified.  The  red  ones  are  lying  in  rolls,  like  coin;  there  are  two  white 
ones  at  a  and  a.  B,  C,  D,  red  corpuscles  in  various  positions,  much  more 
enlarged  ;  E,  one  swollen  to  a  sphere ;  F,  G,  white  corpuscles ;  //,  I,  unusual 
forms  of  red  corpuscles ;  K,  the  red,  treated  with  acetic  acid. 


The  blood  is  of  the  utmost  importance  in  sustaining  life, 
w^hether  it  be  of  the  whole  body  or  of  a  part.  If  an  arm  or  a 
leg  is  tied  in  such  a  Avay  that  the  blood  cannot  get  into  it,  the 
limb  grows  cold,  and  will  gradually  perish  if  kept  tied.  If 
the  greater  part  of  the  blood  is  taken  from  a  person's  body, 
extreme  weakness  follows,   and   then   death.      On  the   other 


48 


PHYSIOLOGY. 


Kand,  if  blood,  properly  prepared  to  prevent  clotting,  is  thrown 
into  the  veins  of  the  tied  limb,  and  is  kept  flowing  in,  tiie  life 
of  the  part  is  preserved.  And  similarly,  when  a  person  has 
bled  a  great  deal,  and  is  in  danger  of  dying,  fresh,  warm  blood 
from  another  person,  or  from  a  sheep,  has  sometimes  been  put 

into  the  veins,  and  has 
saved  life.  This  is  called 
transfusion  of  blood. 

The  red  color  of  the 
blood  is  dne  entirely  to 
the  red  blood-corpuscles  or 
blood-cells.  These  are  soft, 
pulpy  masses,  shaped  like 
round,  flat  cakes,  some- 
times lying  separate,  some- 
times clinging  together  in 
rolls,  like  piles  of  coin. 
They  are  so  small  as  to 
require  rather  a  strong 
microscope  to  show  them. 
There  are  millions  in  a 
single  drop  of  blood,  and 
more  than  ten  millions 
could  lie  side  by  side  on  a 
surface  one  inch  square. 

In  pale,  feeble  persons, 
there  are  usually  too  few 
red  blood-cells.  Iron  is 
often  given  to  such  per- 
sons as  a  medicine.  Iron 
is  the  cause  of  the  red 
color  of  the  blood-cells, 
and  when  taken  as  a  med- 
icine it  may  increase  the  number  of  them. 

Among  several  hundred  of  these  corpuscles  there  is  usually 
one  white  cell,  a  round  clump  of  material,  very  different  from 


Fig.  26.  —  The  heart  and  large  blood-ves- 
sels, in  front.  1,  right  ventricle  ;  2,  left 
ventricle ;  3,  pulmonary  artery,  cut  short; 
4,  4',  4",  aorta,  or  chief  artery;  5,  6,  parts 
of  the  right  and  left  auricle ;  7,  7,  veins 

.  uniting  to  form  the  superior  (upper)  vena 
cava ;  8,  inferior  vena  cava ;  9,  vein  from 
liver ;  +,  arteries  nourishing  the  heart. 


CIRCULATION  AND   RESPIRATION. 


49 


tlie  red. 
red. 


It  is  believed  that  the  white  kind  chano^es  into  the 


THE  MOVEMENT  OF  THE  BLOOD. 

The  blood  is  not  contained  in  the  body  as  water  is  in  a 
sponge.  It  is  contained  in  a  vast  number  of  large  and  small 
tubes  called  blood-vessels,  and  in  the  heart,  which  is  the  central 
point  of  the  whole.  The  blood-vessels  include  arteries,  veins, 
and  capHllaries. 

The  capillaries  are  too  small  to  be  seen  with  the  naked  eye. 
Veins  are  easily  seen  on  the  arm  and  back  of  the  hand.  Arte- 
ries are  smaller  than 
veins,  and  do  not  show 
so  plainly,  but  by  ex- 
amining the  front  of  the 
wrist,  and  the  temples, 
we  may  sometimes  see 
or  feel  them  beating. 
This  beating,  called  the 
pulse,  is  a  sign  that  the 
blood  is  moving;  and 
the  movement  of  the 
blood,  beginning  at  the 
heart,  and  going  through 
arteries,  capillaries,  and 
veins,  and  then  back 
again  to  the  heart,  is 
the  circulation. 

Heart  and  Arteries.  — 
The  heart  is  about  as 
large  as  the  fist  of  the 
person  it  belongs  to. 
left  of  the  middle,  between  the  two  lungs.  It  is  hollow,  to 
contain  blood ;  it  is  composed  chiefly  of  muscle,  which  works 
as  a  person's  hand  does  in  squeezing.  It  is  a  kind  of  little 
force-pump,  so  made  that  when  it  closes,  or  "contracts,"  it 


Fig.  27. — Diagram  of  the  heart,  with  blood 
flowing  in  where  the  arrow  is  placed,  from 
the  upper  cavity  (auricle)  to  the  lower 
(ventricle).  The  large  valve  is  open ;  the 
small  one  closed. 


It  lies  in  the   chest,  a  little  to  the 


50 


PHYSIOLOGY. 


pushes  out  a  stream  of  blood  into  the  great  artery  (aor'ta).  In 
contracting,  the  heart  changes  shape  a  little,  and  its  lower  end 
strikes  against  the  wall  of  the  chest  below  the  left  breast, 
where  it  may  be  felt  beating.     The  aorta,  always  full  of  blood, 

is  distended  by  the  blood 
pushed  into  it;  and  a 
kind  of  wave  of  fulness 
travels  quickly  along 
the  whole  length  of 
the  aorta,  and  into  its 
branches,  large  and 
small.  Each  part  of 
every  artery  swells  for 
an  instant  when  the 
wave  comes.  This  swell- 
ing can  be  felt  and  seen, 
and  is  called  the  pulse. 
If  an  artery  is  cut,  the 
blood  can  be  seen  spurt' 
ing  out  in  regular  jets, 
one  at  each  pulse-beat. 
Capillaries.  —  The 
smallest  arteries  divide  up  into  a  meshwork  of  still  smaller 
blood-vessels,  called  capillary  vessels,  or  capillaries,  from  their 
small  size.^  They  have  no  pulse.  The  walls  of  the  capillaries 
are  thin,  and  fluid  easily  passes  through  to  the  tissues  around 
them  ;  and  it  is  thus  that  the  nourishment  reaches  the  mus- 
cles, bones,  and  all  other  parts  which  require  it.  Capillaries 
are  found  almost  everywhere.  It  is  they  which  bleed  when 
a  pin  is  thrust  into  the  skin.  In  the  stomach  and  intestines 
they  have  much  work  to  do,  both  in  supplying  material  to 
the  glands,  to  form  gastric  juice  and  other  secretions,  and 
in  receiving  the  digested  food.  They  are  found  in  connection 
with  all  the  glands. 

Veins. — While  passing  through  the  capillaries,  the  blood 
1  From  the  Latin  capillus,  a  hair ;  '*  hair-tubes." 


Fig.  28.  — The  same,  having  become  full,  and 
contracting  to  force  the  blood  out  by  the 
passage  shown  by  the  arrow. 


51 


Fig.  29.  -  Heart  and  blood-vessels  of  the  trunk.    A,  right  auricle;  B.  part  of  left  auricle;  .C,  right  ven- 
tricle; /),  part  of  left  ventricle;  /, /,  aorta;  IT.  pulmonary  arterv :  ///.  superior,  and  /r.  inferior,  vena 
cava;   1,  1,  carotid  arteries;  4,  arteries  for  diaphragm:   .5,  for  kidney:  7, 7',  for  the  legs;  a,     ' 
uniting  to  form  the  superior  vena  cava ;    c,  C.  internal  jugular  veins ;  c".  facial  vein 
jugular  veins;  /,  veins  from  liver;  g,  from  kidney;  i,  etc.,  from  lower  limbs. 


,  veins 
d,  d,  external 


52 


PHYSIOLOGY. 


loses  much  of  its  valuable  nutritive  material,  and  also  receives 
some  of  the  waste  or  used-up  material  from  the  parts  it  has 
traversed.  In  doing  this  it  changes  its  color.  In  the  arteries 
it  is  bright  red ;  in  the  veins,  a  dark  red.  If  a  vein  is  cut,  the 
blood  flows  in  a  steady  stream,  not  by  jerks ;  the  vein  has  no 
pulse.     The  walls  of  a  vein  are  softer  than  those  of  an  artery, 


Fig.  30.  —Part  of  the  web  of  a  frog's  foot,  slightly  magnified,  the  blood-vessels 
only  beiag  drawn,  except  in  one  corner,  where  pigment  spots  are  also  shown. 
a,  small  arteries;  v,  small  veins;  the  capillaries  are  the  minute  tubes  join- 
ing the  veins  and  arteries.    The  arrows  show  the  direction  of  the  current. 

and  can  easily  be  pressed  together  so  as  to  stop  the  flow  of 
blood.  To  illustrate  the  circulation  in  the  veins,  tie  a  hand- 
kerchief firmly  around  the  arm  near  the  elbow :  the  veins  will 


CIRCULATION  AND   REBPIBATION. 


68 


at  once  swell,  displaying  a  network 
<i»t'  bluish  lines  just  under  the  skin  of 
the  forearm  and  hand.  This  shows 
that  the  current  in  these  veins  flows 
from  the  hand  towards  the  shoulder ; 
for  if  it  were  the  other  way,  stopping 
the  veins  would  make  them  swell 
above  the  bandage.  The  arteries 
mostly  lie  deeper  than  the  veins,  and 
their  walls  are  firmer,  so  that  a 
moderate  pressure  has  very  little 
effect  on  them :  they  keep  on  pour- 
ing blood  into  the  lower  arm  until 
the  vessels  can  hold  no  more,  and  the 
arm  is  perceptibly  swollen. 

The  veins  are  x^rovided  with  valves, 
arranged  at  short  distances  apart, 
which  keep  the  blood  from  flowing 
the  wrong  way.  In  the  arm  these 
valves  are  arranged  so  as  to  let 
the  current  pass  freely  towards  the 
shoulder  and  trunk.  If  we  hold  the 
hand  up  above  the  head,  we  can  see 
the  veins  shrink  as  the  blood  sinks 
downward,  or,  as  it  were,  drains  away 
from  the  arm  —  which  would  not 
occur  if  the  valves  opposed  it. 

The  following  experiment  further 
shows  the  action  of  the  valves :  Place 
the  tip  of  the  middle  finger  lightly 
and  steadily  on  one  of  the  large  veins 
near  the  knuckles  of  the  other  hand. 


A. 


J 


^A 


Fig.  31.  — The  veins  lying  near  the  surface  of 
the  arm.  A  few  nerves  are  seen  accom- 
panying the  reins.  The  skin  is  removed, 
but  the  fibrous  sheath  covering  most  of  the 
Miuscles  is  left  remaining. 


54 


PHYSIOLOGY. 


With,  the  forefinger  then  stroke  the  vein  so  as  to  push  the 
blood  from  a  portion  of  it,  keeping  the  middle  finger  in  place; 
the  vein  remains  empty  for  a  length  of  an  inch  or  two  from 
the  middle  finger.  Lift  the  forefinger,  and  no  blood  enters 
the  vein:  there  is  a  valve  towards  the  wrist  which  holds  it 
back.     Lift  the  middle  finger,  and  the  vein  fills  instantly.^ 

Pulmonary  Circulation.  —  The  heart  has  just  been  described 
as  a  pump  which  forces  the  blood  through  the  body.  If  we 
now  proceed  to   examine   its   inner    structure,  studying   the 


Fig.  32.  —  Diagram  of  several 
veins  united,  the  current  flow- 
ing upward,  the  valve  open. 


Fig.  33.  —  The  same,  when  the 
valve  is  closed,  owing  to  an 
obstruction  at  a  higher  point. 
Here  the  current  continues  to 
flow,  but  seeks  a  side  channel 
which  is  free. 


arrangement  of  its  valves  and  pipes,  we  find  that  it  is  a  double 
pump.  It  apparently  forms  one  organ ;  but  it  has  a  right  and 
a  left  side,  completely  independent  of  one  another.  The  use 
made  of  this  curious  plan  is  as  follows.  The  right  side  (or 
pump)  forces  blood  into  the  lungs,  where  it  is  purified;  then 
the  blood  flows  back  to  the  heart,  where  the  left  side  (or 
pump)  receives  it,  and  forces  it  through  the  arteries,  capil- 

1  For  experiments  on  veins,  select  persons  with  large  veins ;  adults,  rather 
than  children. 


CIRCULATION  AND   RESPIRATION. 


55 


laries,  and  veins,  as  has  already  been  described.     The  latter 

is  called  the  general  circulation ;  it  carries  out  pure  blood  to 

the  body,  and  brings  back  impure 

blood  to  the  heart.     The  passage 

through   the   lungs    is    called  the 

pulmonary  circulation ;    it  carries 

impure   blood   to  the  lungs,    and 

brings   back    pure   blood    to   the 

heart. 

Eigs.  27  and  28  will  answer 
equally  well  for  either  side  of 
the  heart,  as  both  sides  are  con- 
structed on  the  same  plan.  The 
heart  is  furnished  with  four  sets 
of  valves,  the  use  of  which  is  like 
that  of  ordinary  pump-valves.  One 
is  placed  at  each  of  the  points 
of  discharge  (pulmonary  artery, 
aorta),  opening  outward.  They 
keep  the  blood  from  flowing  back 
into  the  heart  after  it  has  been 
forced  out.  The  other  two  are 
placed  between  the  auricle  and 
the  ventricle,  on  each  side :  they 
keep  the  blood  from  flowing  back 
from  ventricle  to  auricle.  The 
student  will  find  in  Fig.  27  a  suf- 
ficient illustration  of  the  meaning 
of  the  terms  "  auricle  "  and  "  ven- 
tricle." The  figure  stands  for 
either  side  of  the  heart. 


Fig.  34.  —  Diagram  of  circulation.  Tiie 
arrows  indicate  the  direction  of  the  flow. 
Arterial  blood,  red ;  venous  blood,  blue. 


56 


PHYSIOLOGY. 


Hepatic  Circulation.  —  A  third  system  of  circulation  is  that 
which  passes  through  the  liver  (Fig.  34).  The  capillaries  of 
the  digestive  tract  {i.e.  of  the  stomach  and 
intestines)  contain  blood  which  is  rich  in  the 
nutritive  materials  derived  from  the  digestion 
of  food.  These  capillaries  unite,  forming  a 
large  and  important  vessel,  the  portal  vein, 
which  enters  the  liver,  and  there  again  sub- 
divides into  capillaries.  The  load  of  nutri- 
ment contained  in  this  blood  is  chemically 
acted  upon  by  the  liver.  Then,  passing  out 
from  the  liver  by  several  large  veins,  the  food- 
bearing  blood  enters  the  lower  vena  cava,  or 
great  vein  which  discharges  directly  into  the 
right  side  of  the  heart.  Thus  it  enters  the 
great  mass  of  the  blood.  In  a  moment  more 
it  passes  on  to  the  lungs,  where  fresh  oxygen 
is  supplied  to  complete  the  chemical  changes 
it  must  undergo. 

THE  LYMPHATIC  CIRCULATION. 
YiG.  35.  —  Valves  Outside  of  the  blood-vessels  there  is  a  great 
vesser^"^^^^*^^  amount  of  tissue  of  various  sorts.  It  will 
easily  be  understood  that  in  this,  tissue  fluid 
of  some  sort  or  another  must  exist  in  abundance.  If  by  any 
means  the  blood-vessels  could  be  prevented  from  bleeding, 
and  a  cut  were  made  in  the  body,  a  fluid  would  still  be  dis- 


FiG.  36.  —  Lymphatic  vessels  of  the  surface  of  a  finger.    In  the  preparation,  the 
skin  was  dried  and  varnished,  and  the  vessels  appeared  through  the  skin. 


CIRCULATION  AND  RESPIRATION. 


67 


charged  from  the  wound.  This  fluid 
is  called  the  lymph.  It  is  clear  and 
colorless.  It  fills  interstices  and  pores 
innumerable,  in  almost  all  parts  of  the 
body.  It  does  not  remain  still  and 
stagnant  in  the  parts  where  it  happens 
to  be,  but  is  in  constant  motion. 

There  is  a  set  of  very  small  vessels 
(the  lymphatics),  somewhat  resembling 
little  veins,  whose  duty  is  to  take  up 
the  lymph  and  convey  it  towards  a 
spot  where  it  is  discharged  into  the 
general  circulation  of  the  blood.  Pig. 
35  shows  the  valve-structure  of  one  of 
the  lymphatic  vessels.  Fig.  36  shows 
how  numerous  they  are,  and  exhibits 
the  way  in  which  the  smaller  ones 
unite  to  form  larger  trunks  as  they 
run  up  the  finger.  In  Fig.  37  the 
arrangement  for  the  surface  of  an 
arm  is  shown,  and  with  it  are  dis- 
played some  of  the  lymphatic  glands. 
The  latter  are  small  rounded  bodies, 
through  which  the  lymph  has  to  pass, 
and  in  passing  is  acted  on  and  changed 
in  some  way  by  the  gland. 

All  the  lymphatic  vessels  unite  fin- 
ally in  two  large  ones,  situated  inside 
of  the  trunk,  and  these  discharge  into 
the  great  blood-vessels  at  the  upper 
part,  near  the  neck  ;  their  contents  are 
then  taken  rapidly  into  the  heart,  and 
at  once  form  a  part  of  the  blood. 

There  is  no  special  arrangement  for 
making  the  lymph  circulate.  It  moves 
whenever  a  part  of  the  body  is  raised. 


Fi3.  37.  —  Lymphatic  vessels 
of  the  surface  of  the  arm. 
Glands  are  seen  at  7,  8,  11, 
13. 


58 


PHYSIOLOGY. 


or  pressed,  or  shaken,  or  when  the  muscles  act ;  all  these  cause 
some  pressure  on  the  lymphatics,  and  since  the  vessels  allow 
motion  in  only  one  direction,  some  of  the  fluid  is  constantly 
moving  upward,  or  toward  the  central  parts  of  the  body. 

Great  numbers  of  the  lymphatics  begin  in  the  walls  of  the 
intestines,  where  their  function  is  to  take  up  certain  nutritive 


Fig.  38.  — The  heart  and  lungs ;  the  latter  thrown  back  at  the  sides.  The  heart 
is  seen  in  its  envelope,  or  pericardium,  which  is  opened.  4,  left ;  5,  right 
auricle;  6,  vena  cava  superior;  7,  pulmonary  artery;  9,  aorta;  12,  carotid 
artery;  15,  first  rib;  16,  larynx ;  17,  trachea ;  18,  nerve  to  lungs  and  stomach ; 
19,  nerve  to  diaphragm ;  20,  lung ;  22,  diaphragm ;  23,  seventh  rib. 


materials  (the  fatty  substances)  and  convey  them  to  the  blood, 
—  as  will  be  further  explained  in  the  chapter  on  "Food  and 
Digestion.*' 


CIRCULATION  AND  RESPIBATION. 


59 


OXYGENATION. 

The  space  in  tlie  chest  which  is  not  occupied  by  the  heart 
is  filled  by  the  lungs,  which  during  life  are  constantly  taking 
air  in  and  sending  it  out.     The  air,  entering  l)y  the  nostrils  or 


Ficx.  39.  — Diagram  of  the  air-tubes.  1,  thyroid  cartilage  of  larynx;  2,  cricoid 
cartilage  of  larynx;  3,  trachea;  the  divisions  and  subdivisions  are  the 
bronchi. 

mouth,  passes  down  the  trachea,  or  imndpipe,  a  firm,  large 
tube  which  may  easily  be  felt  in  the  front  of  the  neck ;  the 
windpipe  divides  into  two  parts,  one  for  each  lung ;  these  sub- 


60  PHYSIOLOGY. 

divide,  in  tlie  lungs,  into  smaller  tubes  called  bronchial  tubes, 
wMcli  after  much,  branching  end  in  very  small  cavities  or 
ves'ides.  These  vesicles  have  very  thin  walls,  and  close  behind 
their  walls,  networks  of  capillaries,  containing  blood  which 
requires  to  be  purified. 

About  one-fifth  of  the  air  we  breathe  is  oxygen  gas,  an  invis- 
ible, tasteless,  and  odorless  substance,  which  we  could  not  tell 
from  common  air  by  ordinary  means,  if  it  were  put  before  us 
in  a  pure  state.  Oxygen,  however,  is  the  part  of  air  which 
supports  life.  Air  deprived  of  it  could  be  breathed,  but  a 
person  would  die  in  such  air  as  soon  as  if  he  were  under  water. 
This  oxygen  has  the  power  of  passing  through  the  thin  walls 
of  the  vesicles  and  those  of  the  capillaries  5  and  having  done 
so,  it  is  at  once  absorbed  by  the  red  corpuscles,  v/hose  duty  it 
is  to  carry  it  all  over  the  body  for  use  at  all  points.  When  it 
comes  to  any  place  where  it  is  needed,  it  leaves  the  blood-cells 
just  as  quickly  as  it  went  to  them  in  the  lungs.  "  Oxygena- 
tion "  is  the  process  of  supplying  the  blood  and  tissues  with 
oxygen. 

The  use  of  oxygen,  in  all  the  parts  to  which  it  is  carried, 
is  to  unite  with  the  materials  of  the  parts  and  change  them. 
This  change  is  called  oxidation.  It  is  the  same  that  occurs 
outside  of  the  body  in  burning.  But  combustion,  or  burning, 
often  goes  on  so  slowly  that  no  flame  and  but  little  heat  is 
produced.  It  is  this  slow  oxidation  that  occurs  in  the  body. 
Something  like  it  may  be  seen  when  a  pile  of  compost,  a  heap 
of  sawdust,  or  a  few  greasy  rags  thrown  together,^  grow  hot, 
and  smoke,  when  left  to  themselves. 

To  see  how  a  thing  may  burn  without  being  destroyed  at  all, 
look  at  a  fresh  candle-wick  or  lamp-wick  when  lighted.  It 
soaks  up  the  wax  or  the  oil,  and  makes  that  burn,  while 
itself  hardly  changes  color.  This  is  a  good  example  of  some 
things  which  occur  in  the  body.  A  muscle,  for  instance,  while 
at  work,  takes  much  nutritious  material  from  the  blood  and 
burns  it  in  a  quiet  way,  without  flame  ;  the  muscle,  after  work- 

1  N.B.  — Such  heaps  of  rags  or  sawdust  may  blaze,  and  set  buildings  on  fire. 


CIRCULATION  AND  BESPIRATION.  61 

ing,  looks  as  before,  tlioagh.  it  is  warmer,  and  the  blood  which 
has  passed  through  it  is  warmer  than  before. 

The  materials  burned  in  the  body  are  such  as  could  be 
burned  in  a  stove.  For  instance,  it  would  be  possible  to  build 
a  fire  of  bread,  dried  fruit,  or  even  dried  meat,  while  fat  burns 
very  readily.  If  burnt  in  this  way,  these  bodies  change  to 
three  substances,  principally, — water,  carbonic  acid  gas,  and 
the  nitrogenous  substance  called  urea. 

The  same  substances  are  produced  when  the  materials  of 
the  body  are  consumed  in  vital  processes.  They  are  easily 
absorbed  or  dissolved  by  the  blood.  When  much  carbonic 
acid  has  been  taken  up,  and  much  oxygen  lost,  by  the  blood, 
its  color  becomes  dark,  and  it  requires  to  be  purified  in  the 
lungs  by  discharging  its  carbonic  acid  and  taking  in  a  fresh 
stock  of  oxygen. 

The  fact  that  combustion  occurs  in  the  body  shows  that 
food  can  be  considered  as  a  fuel,  or  a  means  of  keeping  the 
body  warm. 

TEMPERATURE  OF  THE  BODY. 

The  temperature  of  a  healthy  man's  body  is  very  nearly 
99°  F.  It  varies  a  fraction  of  a  degree  from  hour  to  hour ; 
and  exercise  increases  it  a  little.  In  fever,  it  rises  several 
degrees. 

The  bulb  of  a  thermometer,  placed  on  the  skin,  will  usually 
register  a  much  lower  temperature  than  99°.  The  skin,  there- 
fore, is  usually  much  cooler  than  the  interior  parts ;  in  fact, 
one  of  its  functions  is  to  cool  the  body,  —  throwing  off  a  part 
of  the  heat  which  is  being  produced  all  the  time,  and  which,  if 
accumulated  in  the  body,  would  become  so  great  as  to  destroy 
life. 

Perspiration  has  a  great  effect  in  cooling  the  skin.  In  fact, 
when  the  thermometer  stands  at  99°  or  higher,  if  the  skin 
does  not  perspire,  the  body  will  quickly  grow  hot  and  feverish ; 
while  this  degree  of  heat  is  easily  borne  by  a  person  whose 
body  perspires  naturally. 


62  PHYSIOLOGY. 

It  may  be  asked  wliy  it  is  necessary  for  the  body  to  pro- 
duce so  much,  heat  which,  it  is  obliged  to  get  rid  of.  The 
question  is  especially  interesting  in  hot  weather.  A  good  gen- 
eral answer  is  this :  that  the  chemistry  of  the  interior  of  the 
body  cannot  be  carried  on  at  a  lower  temperature,  in  mauo 
Fishes,  reptiles,  and  frogs  have  a  much  lower  temperature; 
they  are  "cold-blooded"  creatures. 

Blushing  (or  flushing)  indicates  the  fulness  of  the  capillary 
blood-vessels  in  the  skin,  due  to  the  action  of  nerves  which 
are  controlled  by  the  feelings  of  the  mind  (shame,  modesty, 
timidity).  Fear,  like  cold,  produces  paleness.  Anger  and 
grief  sometimes  cause  a  flush,  sometimes  pallor. 

BREATHING. 

Breathing  is  a  remarkable  muscular  action.  To  an  untaught 
person  the  breath  seems  to  flow  in  and  out  in  a  mysterious 
way,  of  its  own  accord.  It  is  so  plainly  necessary  to  life  — 
and  stopping  it  will  so  quickly  put  an  end  to^  life  —  that  the 
Eomans  used  the  word  "breath"  (anima)  for  "soul";  while 
the  word  for  "breathing"  (spiritus)  also  signifies  "spirit."  The 
Greeks  did  the  same  with  their  words  (psycJie  and  pneuma) . 

The  word  "inspiration"  means  breathing  in,  or  "taking 
breath";  "expiration"  is  breathing  out;  "respiration"  in- 
cludes both,  and  denotes  breathing  in  general. 

It  is  very  important  to  understand  the  mechanism  of  breath- 
ing, as  we  may  thereby  be  enabled  to  save  life. 

The  chest  may  be  considered  as  a  pair  of  bellows,  which 
sucks  the  air  in  when  it  is  opened.  It  differs  from  the  bellows 
in  having  but  one  hole  (windpipe)  for  both  the  in-coming  and 
the  out-going  air. 

The  frame,  or  basket,  called  the  cJiest,  is  formed  of  movable 
parts.  Each  rib  is  hinged  to  the  spine,  aud  can  move  a  little, 
upward  and  outward,  when  certain  muscles  pull  upon  it ;  this 
movement  makes  the  cavity  of  the  chest  wider,  and  corre- 
sponds to  the  opening  of  the  bellows.     We  do  not  move  the 


CIRCULATION  AND  RESPIRATION.  63 

chest  muscles  in  breathing  out :  the  ribs  sink  of  themselves, 
from  their  own  weight  and  elasticity.      So  the  bellows  falls 
by  its  own  weight,  forcing  out  the  air  from  the  nozzle. 
Some  of  the  following  experiments  may  here  be  useful :  — 

1.  At  a  convenient  time,  remove  all  belts  and  other  things 
that  confine  the  body.  Let  the  arms  hang  by  the  sides.  Tie 
a  piece  of  twine  closely  around  the  body,  next  the  skin,  about 
six  or  seven  inches  below  the  collar-bone.  Then  draw  a  full 
breath,  and  feel  how  the  twine  cuts,  showing  that  the  chest 
enlarges  when  we  breathe  in. 

2.  Again,  using  a  tape-measure,  note  the  circumference  of 
the  chest  when  at  rest,  when  quite  full  of  air,  and  when 
emptied  as  much  as  possible.  (Assistance  may  be  required.) 
The  arms  are  not  raised. 

3.  Measure  the  expanded  chest  with  the  arms  raised,  and 
notice  that  it  is  still  larger  than  before.  This  is  due  to  the 
action  of  some  muscles  at  the  shoulder,  which,  when  the  arm 
is  raised,  draw  strongly  upon  the  sides  of  the  chest  in  such  a 
way  as  to  open  or  expand  it. 

4.  One  person  should  stand  with  his  arms  hanging  by  his 
sides.  A  taller  person  behind  him  grasps  his  arms  and  quickly 
raises  them  sideways,  so  that  the  hands  meet  above  the  head. 
It  will  be  noticed  that  the  air  is  sucked  in  at  the  mouth  while 
this  movement  is  being  made.  By  raising  the  arms  above  the 
head,  we  can  make  air  enter  the  chest  of  a  person  who  has 
been  suffocated,  and  has  ceased  to  breathe.  By  keeping  up 
the  process  for  a  long  time,  the  blood  becomes  slowly  purified, 
the  heart  is  induced  to  beat,  first  feebly  and  then  more  strongly, 
until  the  breath  comes  spontaneously.  This  constitutes  "  arti- 
ficial respiration,"  described  in  an  appendix. 

Abdominal  Respiration.  —  The  partition  which  separates  the 
chest  from  the  abdo'men  is  called  the  diaphragm.  It  is  not 
flat,  but  rounds  upward,  as  seen  in  Fig.  40.  It  consists  chiefly 
of  muscle,  with  firm  white  tendons  at  the  borders.  Like  other 
muscles,  it  has  the  power  of  shortening.  Being  of  a  curved 
form,  it   becomes    straighter  when   it   shortens,  the  effect  of 


64 


PHYSIOLOGY. 


which  is  to  enlarge  the  lower  part  of  the  chest.  Or  in  other 
words,  by  its  downward  pull  it  causes  a  sort  of  suction.  This 
draws  in  air  by  the  windpipe,  and  produces  breathing.  Dia- 
pJiragmat'ic  breathing  is  the  name  given  to  this  action.  Another 
name  given  to  it  is  abdominal  breathing,  owing  to  the  fact  that 
the  region  of  the  stomach  and  bowels  is  pushed  downwards 
and  forwards  during  inspiration.  It  is  more  distinctly  seen 
in  men  than  in  women,  while  chest  breathing  is  more  distinct 


Fig.  40.  —  Diagrammatic  sections  of  the  body  in  A,  inspiration;  B,  expiration, 
r?'.  trachea ;  St.  sternum;  i).  diapliragm;  J.&,  abdominal  walls.  The  shad- 
ing roughly  indicates  the  stationary  air, 

in  women.  In  this  form  of  breathing,  expiration  is  aided  by 
the  muscles  of  the  abdomen,  as  may  easily  be  felt  with  the 
hand.     Fig.  40  represents  both  forms  combined. 

We  seldom  breathe  as  fully  as  we  can.  Suppose  that  the 
amount  of  air  in  the  lungs  of  an  average-sized  adult,  while 
sitting  quietly,  equals  about  200  cubic  inches.  In  drawing 
an  ordinary  breath,  he  takes  in  about  30  cubic  inches  more ; 


CIRCULATION  AND   RESPIBATION.  65 

but  by  a  strong  effort  he  can  inhale  four  times  as  much  air, 
or  say  130  cubic  inches,  making  the  lungs  to  contain  330  cubic 
•inches.  And  by  a  reverse  effort  he  can  force  out  so  much  air 
as  to  lower  the  quantity  to  100  cubic  inches. 

There  are  instruments  called  spirometers,  for  measuring  the 
amount  of  air  that  can  be  forced  out  in  breathing  after  taking 
a  very  full  breath.  This  amount,  on  an  average,  may  be  seen 
from  the  above  figures  to  be  about  230  cubic  inches ;  it  is  com- 
monly termed  the  "vital  capacity." 

The  "  shallow  "  breathing  is  all  that  we  require  when  sitting 
still.  When  exercising,  the  work  done  by  the  muscles  at  once 
throws  into  the  blood  an  increased  amount  of  waste  material 
and  carbonic  acid,  which  comes  to  the  lungs,  and  makes  us 
feel  that  we  need  to  get  rid  of  it  by  full  breathing.  A  weak 
person's  lungs  and  chest  soon  grow  tired  in  exercising,  and  he 
becomes  uncomfortable,  feeling  the  need  of  breath,  but  unable 
to  take  it.  The  chest  and  diaphragm  must,  therefore,  be  trained 
by  exercise  to  be  able  to  do  hard  and  rapid  work  in  breathing. 
Soldiers,  runners,  oarsmen,  and  many  others  greatly  need  this 
training.     But  it  is  good  for  all  persons. 

The  pulse  becomes  faster  when  the  breathing  does ;  their 
duties  are  parts  of  one  great  work,  and  they  assist  one  another. 

A  man  sitting  at  rest  breathes  about  sixteen  times  in  and 
out  every  minute.  His  pulse  is  rather  less  than  seventy  in  a 
minute.  In  women  and  children  these  numbers  are  larger. 
Exercise  increases  them  very  much.  They  are  lessened  by 
lying  down,  increased  by  standing.  They  may  also  differ 
considerably  in  healthy  persons  of  the  same  age  and  sex. 

A  sigh  is  a  full  breath  not  caused  by  exercise.  Panting  is 
a  series  of  hasty  breaths.  Sobbing  is  a  spasmodic  jerkin g-in 
of  the  breath.  Hiccup  is  like  sobbing,  with  a  catch  in  the 
throat  added.  Coughing  is  a  violent  throwing  out  of  breath, 
with  a  catch  or  partial  closing  of  the  throat,  so  as  to  make  a 
barking  sound.  Sneezing  is  a  violent  throwing  out  of  breath 
without  the  catch. 


66  PHYSIOLOGY. 


HYGIENE. 


Temperature.  —  When  the  blood  circulates  rapidly  and  the 
heart  and  pulse  beat  strongly,  a  person  is  usually  in  good 
health.  Such  a  one  is  less  apt  to  take  cold  than  a  person  in 
whom  the  circulation  is  sluggish ;  he  is  less  easily  chilled  in 
bathing,  and  is  less  liable  to  have  cold  hands  and  feet. 

"  Keep  the  head  cool  and  the  feet  warm "  is  one  of  the 
wisest  medical  proverbs.  To  prevent  over-heating  the  head, 
let  the  room  you  study  in  not  be  warmer  than  about  65°;^  a 
healthy  child  from  ten  to  fourteen  years  of  age  seldom  requires 
greater  heat.  Do  not  study  with  the  head  near  a  hot  lamp  or 
over  a  register. 

To  keep  the  feet  warm  take  plenty  of  exercise  every  day, 
and  do  not  sit  still  (at  the  age  of  twelve)  more  than  an  hour 
at  a  time ;  the  air  near  the  floor  should  not  be  below  60° ;  the 
feet  must  never  be  kept  in  wet  shoes  and  stockings.  Persons 
who  live  in  too  hot  rooms  are  apt  to  have  frequent  colds. 

There  is  a  great  difference  in  people  as  regards  the  heat 
they  require.  Europeans  generally  prefer  the  thermometer  at 
about  60° ;  the  inhabitants  of  the  United  States  and  Canada, 
near  70°.  Some  require  thicker  clothes  than  others.  Little 
infants  and  very  old  persons  must  be  kept  thoroughly  warm, 
for  they  may  easily  be  killed  by  the  cold. 

In  summer,  a  di-y  heat  of  from  100°  to  120°,  which  is  ex- 
perienced in  Arizona,  is  said  to  be  more  easily  borne  than  a 
moist  heat  of  90°,  such  as  we  often  have  during  "  dog  days." 

Rmming  is  one  of  the  best  exercises  for  improving  the  cir- 
culation and  power  of  breathing.  It  is  natural  to  little  chil- 
dren, and  might  .well  be  practised  by  those  who  do  not  con- 
sider themselves  little.  In  the  beginning  one  should  take 
very  short  runs,  at  moderate  speed,  and  gradually  increase 
both  length  and  speed.  All  exercise  that  is  useful  to  health 
ought  to  quicken  the  pulse  and  breathing  considerably  ;  run- 

1  Some  authorities  say  70°. 


CIRCULATION  AND  BESPIEATION.  67 

ning  does  this  more  than  most  other  kinds  of  exercise,  and 
there  are  few  young  persons  who  cannot  bear  the  strain. 

Clothing. — A  bandage  around  a  limb  checks  the  circula- 
tion, making  the  blood  stagnate.  By  winding  a  string  tightly 
around  a  finger,  we  can  squeeze  out  most  of  the  blood  and 
prevent  fresh,  warm  blood  from  entering,  which  makes  the 
finger  cold.  Tight  garters  prevent  the  free  return  of  the 
blood  from  the  leg  and  foot ;  and  thus  tend  to  cause  disease 
of  the  veins.  In  fact,  tight  clothes  at  any  point  interfere  with 
circulation  and  thus  cut  off  "the  blood,  which  is  the  life," 
from  a  part  of  the  system. 

The  practice  of  dressing  tightly  in  order  to  show  the  form 
of  the  body  and  make  it  look  more  slender  is  common  and 
generally  injurious.  It  prevails  among  the  vain  of  both  sexes. 
Tight  clothes  interfere  with  several  of  the  greatest  and  most 
important  of  the  functions  of  the  body.  They  prevent  a  full 
breath  being  taken,  and  thus  continually  starve  the  blood  by 
limiting  the  amount  of  oxygen  that  enters  the  lungs.  They 
make  it  difficult  to  use  the  muscles  vigorously,  and  so  check 
exercise.  They  press  on  the  stomach,  liver,  and  intestines, 
interfering  with  their  movements,  and  so  hindering  digestion 
and  producing  constipation.  And  finally,  they  check  the  cir- 
culation in  the  limbs,  as  has  already  been  stated.  The  whole 
effect  of  tight  dressing  is  injurious. 

A  person  when  clothed  ought  to  be  able  to  lift  the  arms 
straight  up  so  as  to  touch  the  hands  above  the  head.  He 
ought  to  be  able  to  draw  a  full  breath  without  a  feeling  of 
tightness  around  the  chest  or  abdomen.  The  use  of  tight 
belts  is  bad.  Tight  collars  or  neckties  make  the  head  and  face 
full  of  blood,  especially  when  we  stoop  in  study ;  they  are 
injurious  to  the  eyes  and  may  cause  nosebleed. 

There  is  one  exception  to  the  rule  about  tight  clothing. 
When  there  is  a  tendency  to  diarrhoea,  it  is  very  useful  to 
wear  a  flannel  belt  about  the  abdomen,  rather  tightly  applied. 

Asphyxia  or  Suffocation  can  be  produced  by  sudden  stoppage 
of  breath  (as  in  drowning  or  strangling),  or  b}^  some  poisonous 


68  PHYSIOLOGY. 

gases.  In  asphyxia  the  blood  contains  much  carbonic  acid, 
and  little  or  no  oxygen.  The  first  and  most  important  thing 
to  do  for  its  relief  is  to  bring  back  the  breathing.  If  a  person 
has  only  just  stopped  breathing,  a  slap  on  the  face  with  the 
hand  or  a  wet  cloth,  may  start  respiration.  If  asj)hyxia  has 
lasted  for  some  time,  there  should  be  not  a  moment's  delay  in 
establishing  artificial  respiration,  according  to  methods  given 
later. 

Fresh  Air.  —  Our  bodies  are  kept  warm  by  the  combustion 
of  the  food  we  take.  The  more  food  is  burned,  the  more  air  is 
taken  into  the  lungs.  It  is  very  desirable  that  the  air  should 
be  pure  at  all  times.  When  exercising,  we  draw  in  much 
more  air  —  and  it  ought  to  be  as  fresh  as  possible.  When 
sitting  at  rest,  especially  when  studying,  we  need  the  purest 
and  best  air  to  enable  us  to  think  well.  In  close,  crowded 
rooms  people  cannot  study  nearly  as  well  as  in  well-aired  ones ; 
they  become  sleepy  and  tired ;  the  head  grows  hot,  and  aches. 

Air  just  breathed  out  of  the  lungs  is  very  impure  from  the 
carbonic  acid  and  other  harmful  gases  which  it  contains.  The 
perspiration  from  the  skin  increases  the  impurity  of  the  air 
of  rooms.  In  close  rooms  the  air  remains  bad  until  it  is  taken 
out  by  the  windows,  doors,  or  ventilators.  Ventilation  means 
removing  the  bad  air.  It  takes  but  a  few  minutes  ^  for  the  air 
in  an  ordinary  unventilated  schoolroom  to  become  bad,  and  to 
keep  it  good  we  need  to  change  the  whole  of  it  several  times 
every  hour.  Schoolrooms  are  very  rarely  so  constructed  that 
they  can  be  ventilated  well. 

It  is  often  necessary  to  open  windows.  There  is  danger  in 
doing  this  that  a  draught  of  cold  air  may  strike  on  some  per- 
son, producing  colds,  face-ache,  ear-ache,  or  worse  complaints. 

Bleeding.  —  When  bleeding  is  profuse,  it  can  almost  always 
be  stopped  by  firm  pressure  upon  the  bleeding  spot  with  the 
thumbs  or  a  hard  roll  of  cloth.  If  necessary,  keep  up  the 
pressure  until  a  surgeon  comes. 

Moderate  bleeding  often  stops  of  itself  by  the  formation  of 
1  Perhaps  on  an  average  we  may  say  ten  minutes. 


I 


CIBCULATION  AND  BESPIBATION.  69 

a  clot  in  the  wound;  wliicli  is  nature's  way,  and  is  often  better 
than  washing  with  water. 

Bleeding  by  jerks  or  spurts  comes  from  an  artery.  To  stop 
it,  press  on  the  artery  just  above  the  cut  (between  it  and  the 
heart)  until  a  surgeon  comes. 

Bleeding  in  a  steady  stream  is  from  a  vein,  and  may  be 
stopped  by  a  pad  of  cloth  tied  upon  the  spot. 

In  nosebleed,  sit  with  the  head  slightly  bent  over  the  basin ; 
loosen  the  neck  clothing ;  put  something  cold  on  the  neck  or 
spine  ;  do  not  blow  the  nose. 

Fainting  is  a  sudden  weakening  of  the  action  of  the  heart ; 
the  person  may  feel  sick  and  dizzy,  the  action  of  the  brain 
ceases,  and  consciousness  is  lost.  When  a  person  faints,  he 
may  fall  to  the  ground ;  he  usually  attracts  notice,  and  people 
are  led  by  curiosity  to  crowd  around  him,  which  is  the  worst 
thing  they  can  do;  for  it  keeps  him  from  getting  what  he  most 
needs, — the  fresh  air.  Lay  the  person  flat  on  his  back.  Make 
the  clothing  around  the  neck  perfectly  loose.  Do  the  same 
with  the  chest  and  abdomen.  Open  the  windows.  Fan  the 
face  or  sprinkle  it  with  cold  water  to  excite  breathing.  Put 
smelling-salts  to  the  nose  to  stimulate  the  lungs  and  heart. 


STIMULANTS  AND   NARCOTICS. 

One  of  the  first  effects  of  alcoholic  drinks  is  seen  in  the 
skin,  which  becomes  flushed,  owing  to  an  increased  amount  of 
blood  in  its  capillaries.  This  is  the  effect  of  a  nervous  action, 
a  sort  of  weakening.  In  people  who  use  these  drinks  often 
the  capillaries  (of  the  nose  and  cheeks)  remain  enlarged, 
making  those  parts  permanently  red  —  a  sign  of  injured  cir- 
culation. Something  of  that  sort  goes  on  inside  of  the  body ; 
for  instance  in  the  kidneys,  which  are  often  injured  by  drink. 

The  alcoholic  drinks  at  first  increase  the  frequency  of  the 
pulse  and  breathing.  They  "  stimulate ''  or  spur  on  the  heart 
and  lungs  to  work  more  rapidly.  Hence,  they  have  a  place  in 
Medicine.    But  they  belong  to  the  class  of  remedies  which  are 


70  PHYSIOLOGY. 

capable  of  destroying  life,  and  wlien  a  fatal  dose  has  been 
taken,  one  of  its  effects  is  seen  in  the  pulse  and  breathing, 
which  grow  slower  and  finally  cease. 

Alcoholic  drinks  lower  the  temperature  of  the  body.  This 
is  exactly  the  opposite  of  what  we  should  suppose  when  we 
see  how  flushed  the  face  looks  after  drinking.  It  is  never- 
theless true,  and  can  easily  be  proved  by  the  test  of  the  ther- 
mometer when  large  quantities  are  taken.  It  is  also  apparent 
in  persons  who  are  "dead  drunk."  If  a  person  is  going  to 
be  exposed  to  severe  cold,  which  may  possibly  endanger  his 
life,  the  danger  is  very  much  increased  by  drinking  spirits. 

Exhaustion  from  extreme  fatigue,  exposure  to  heat  or  cold, 
or  hunger  or  bleeding,  produce  faintness,  which  is  due  in 
part  to  weakness  of  the  heart.  A  generally  safe  remedy  for 
such  a  state  is  a  little  ammonia  (hartshorn).  Wine  and  spirits 
are  often  used  to  restore  x^eople  who  are  "  far  gone,"  that  is,  too 
weak  even  to  eat ;  but  it  must  be  remembered  that  such  cases 
are  exceptions.  For  less  severe  fatigue  (as  when  one  has 
walked  twice  as  far  as  one  is  accustomed  to  do)  a  safe  restora- 
tive is  found  in  tea  or  coffee  or  cocoa. 

Persons  who  require  to  use  all  their  strength  and  to  keep  it 
up  for  a  long  time,  as  pedestrians  or  athletes,  find  that,  on 
the  whole,  the  effect  of  alcoholic  drink  is  not  good :  it  does 
not  increase  strength. 

A  drink  of  an  alcoholic  beverage  is  likely  to  make  a  person 
feel  stronger  for  a  while.  The  sensation  is  not  a  truth-telling 
one.  If  the  strength  (of  the  hand,  for  instance)  be  then  meas- 
ured, it  will  not  be  found  to  be  greater. 

The  effect  of  tobacco,  in  inexperienced  persons,  is  to  pro- 
duce a  great  feeling  of  weakness.  The  heart  shares  in  this 
influence.  The  pulse  becomes  feeble,  and  the  circulation  in 
the  skin  is  lessened.  If  a  person  becomes  a  regular  user  of 
tobacco,  this  effect  is  no  longer  noticed  as  a  rule ;  but  in  many 
persons  another  and  a  most  unpleasant  effect  comes  to  be 
noticed,  namely,  palpitation  of  the  heart,  —  a  disease  which 
is  not  likely  to  cause  death,  but  which  causes  much  anxiety 


CIRCULATION  AND  RESPIRATION.  71 

of  mind  mid  gives  great  discomfort.  Palpitation,  in  such 
cases,  may  be  looked  upon  as  proof  that  the  system  is  in  a  bad 
condition,  unable  to  carry  on  its  work  through  weakness. 


SYNOPSIS. 

The  blood,  forming  -^^  of  the  weight  of  the  human  body,  is  the 
universal  distributor  of  nutrition,  reaching  almost  all  parts  of  the 
frame.  It  is  composed  of  serum,  fibrin,  and  corpuscles.  The  "clot" 
of  blood  contains  the  two  latter  elements.  Blood  contains  the  equiva- 
lent of  all  the  materials  found  in  the  structures  of  the  body.  Chemi- 
cally analyzed,  it  resembles  milk  and  muscular  tissue. 

Tying  a  limb  so  as  to  check  the  flow  of  blood  will  m  time  cause  it 
to  perish.  Death  follows  great  loss  of  blood ;  transfusion  sometimes 
saves  life. 

The  waste  jDroducts  of  the  system  are  carried  off  by  the  blood  to 
the  excretory  organs,  —  skin,  lungs,  kidneys,  etc. 

The  color  of  the  blood  is  due  to  the  red  corpuscles ;  their  color 
again  is  due  to  the  presence  of  compounds  of  iron,  a  remedy  useful 
for  persons  whose  blood  is  thin;  i.e.  who  have  too  few  red  blood- 
corpuscles. 

The  white  corpuscles  are  very  few  in  number  compared  with  the 
red ;  the  latter  are  supposed  to  originate  from  the  former. 

The  blood  is  contained  in  a  system  of  tubes  (blood-vessels)  and 
the  heart. 

The  blood-vessels  include  arteries,  without  valves  and  with  pulsa- 
tions ;  capillaries  (extremely  fine),  without  either ;  and  veins,  with 
valves  and  without  pulsations.  The  general  circulation  starting  at 
the  heart  (left  side)  passes  through  arteries,  capillaries,  veins,  back  to 
the  heart  (right  side).  The  heart  acts  as  a  pump;  its  strokes  give  an 
impulse  which  travels  along  the  arteries,  and  is  called  the  pulse.  The 
capillaries  are  the  vessels  which  bring  the  blood  directly  to  the  tissues 
which  need  nourishment.  They  also  furnish  material  for  the  glands 
to  form  secretions  from,  and  they  take  up  the  waste  matters  of  the 
body,  as  before  said.  After  passing  from  the  capillaries  to  the  veins, 
the  blood  has  become  dark  in  color  from  loss  of  oxygen  and  increase 
of  impurity ;  it  is  then  called  venous  hlood.  (Experiment  on  valves  in 
veins.) 

Venous  blood  entering  the  right  half  of  the  heart  is  pumped  from 


72  PHYSIOLOGY. 

that  part  to  the  lungs,  where  it  becomes  purified  and  oxygenated  ; 
thence  it  returns  to  the  left  half  of  the  heart,  which  forces  it  to  re- 
sume its  general  circulation  once  more.  This  intermediate  passage 
is  called  the  pulmonary  circulation. 

The  hepatic  circulation  is  the  system  which  collects  the  blood  from 
the  capillaries  of  the  stomach  and  intestines  and  compels  it  to  pass 
through  the  liver.  This  portion  of  the  blood  is  rich  in  nourishment 
derived  from  food ;  it  undergoes  certain  changes  in  the  liver  before 
passing  on  to  the  great  vein  near  the  heart. 

The  lungs  fill  the  chest  to  the  right  and  left  of  the  heart.  The  air 
enters  through  the  trachea,  which  divides  and  subdivides  into  the 
bronchial  tubes,  which  open  into  the  vesicles.  From  these  the  oxygen 
of  the  air  passes  to  the  blood  in  the  capillaries,  where  it  is  fixed  by 
the  red  corpuscles  and  so  carried  all  over  the  body.  Oxygen  causes 
changes  in  the  tissues  similar  to  those  of  burning;  the  materials 
burned  are  those  supplied  by  the  food,  and  the  result  of  combustion  is 
chiefly  water  and  carbonic  acid.  The  latter  is  taken  up  by  the  blood, 
giving  to  it  the  dark  color  of  "venous"  blood;  carried  to  the  lungs, 
the  carbonic  acid  is  there  discharged  and  breathed  out. 

The  body  heat  is  near  99°  F.  At  the  skin  it  is  usually  much  less. 
The  skin  regulates  the  heat  in  the  body ;  when  the  heat  is  excessive, 
perspiration  occurs  .and  cools  the  skin  rapidly. 

Blushing  is  a  sudden  filling  of  the  capillaries  of  the  skin.  Some 
emotions  cause  pallor  ;  some,  flushing. 

The  word  "  breath  "  in  Latin  and  Greek  was  the  same  as  "  soul " 
or  "spirit,"  since  breath  is  necessary  to  life.  Breathing  is  caused  by 
the  basket-shaped  chest  enlarging  and  sucking  in  air  through  the 
trachea,  and  afterwards  diminishing  and  expelling  the  air.  Muscles 
attached  to  the  shoulders  and  neck  and  ribs  draw  the  chest  open ;  the 
diaphragm  has  a  similar  and  important  action ;  but  in  expiration  no 
muscular  act  is  needed,  since  the  chest  contracts  by  its  own  weight 
and  elasticity.    (Experiments.) 

A  man  at  rest  breathes  in  and  out  about  30  cubic  inches.  By  mak- 
ing efforts  he  can  make  the  amount  230  cubic  inches.  It  is  important 
to  develop  the  chest  so  as  to  take  in  a  liberal  amount  of  air.  Exer- 
cise which  develops  the  lungs  and  strengthens  the  muscles  of  respira- 
tion is  of  great  importance. 

The  pulse  sympathizes  with  the  respiration.  The  rate  is  variable 
in  different  persons;  in  men  the  pulse  is  usually  under  70  and  the 
respiration  under  17  per  minute ;  in  women  and  children  more  rapid. 


CIRCULATION  AND   EESPIEATION.  73 

The  position  of  the  Doay  iiitiuences  them.  Exercise  hastens  them 
very  much. 

Sighing,  sobbing,  coughing,  etc.,  are  peculiar  forms  of  breathing. 

A  vigorous  circulation  is  a  sign  of  good  health,  and  keeps  off  a 
tendency  to  colds.  Exercise  promotes  it ;  too  hot  rooms  weaken  the 
circulation.  65°  is  a  good  average  temperature  in  winter.  In  sum- 
mer moist  heat  is  very  hard  to  bear.  Running  is  one  of  the  best  exer- 
cises for  the  circulation  and  respiration. 

A  tight  bandage  around  a  part  arrests  its  circulation  and  interferes 
with  its  nutrition.  The  same  is  true  of  tight  garters  and  tight  cloth- 
ing in  general;  another  evil  effect  is  seen  in  the  checking  of  respi- 
ration. Belts,  collars,  neckties  and  the  chest  clothing  often  impede 
circulation  and  breathing.  A  wide  flannel  waist-belt  is  of  use  in  pre- 
venting diarrhoea. 

Asphyxia  is  produced  by  strangling  or  by  poisonous  gases.  The 
blood  is  deprived  of  oxygen  and  ceases  to  support  life.  If  life  is  only 
seemingly  extinct,  it  may  be  restored  by  artificial  respiration. 

Fresh  air  becomes  polluted  by  the  presence  and  breath  of  numbers 
of  people  ;  it  then  contains  less  oxygen  and  is  less  invigorating,  so 
that  study  becomes  difficult.  Ordinary  schoolrooms  are  very  seldom 
well  ventilated.  Each  scholar  should  have  1800  ^  cubic  feet  of  fresh 
air  supplied  by  ventilation  every  hour ;  frequently  not  one-tenth  as 
much  is  supplied. 

Bleeding  can  be  stopped  by  pressure  on  the  spot.  If  the  blood 
comes  in  jerks,  we  may  apply  pressure  firmly  just  above  the  cut. 

Fainting  is  due  to  failure  of  the  heart  to  act.  The  remedies  are 
fresh  air,  recumbent  posture,  loosening  the  clothes  of  neck  and  chest, 
sprinkling  the  face. 

Alcoholic  drinks  at  first  increase  the  frequency  of  the  pulse  and 
breathing.  This  medicinal  effect  can  be  made  useful  in  cases  of 
exhaustion.  A  flushing  of  the  skin  is  common  and  may  injure  the 
complexion  permanently.  Excessive  amounts  may  so  paralyze  both 
respiration  and  pulse  as  to  cause  death.  A  lowering  of  the  tempera- 
ture occurs.  For  athletes  alcoholic  drinks  are  im advisable;  they  do 
not  add  to  the  strength. 

Tobacco  in  beginners  greatly  weakens  the  pulse  and  breathing.  It 
not  infrequently  causes  a  disease  —  palpitation  of  the  heart  —  in  those 
accustomed  to  it. 

1  This  is  a  moderate  estimate. 


74  PHYSIOLOGY, 


SUGGESTED   QUESTIONS. 

Amount  of  blood  in  body :  its  component  parts  ;  coagulation ;  com- 
ponents of  clot ;  nutritious  properties  of  blood ;  chemical  resemblance 
to  some  other  substances  ;  waste-products  ;  effect  of  removal  of  blood; 
transfusion. 

Red  corpuscles  :  shape,  number,  deficiency  of ;  iron  in.  White  cor- 
puscles. 

Structures  which  contain  the  blood :  general  appearance  of  blood- 
vessels. Heart:  size;  position;  tissue  composing  it;  mechanical  func- 
tion; pulsation  felt.  Aorta  and  arteries  ;  pulse  ;  wounds.  Capillaries  : 
pulsation;  nutrition;  secretion;  digestion.  Veins:  waste  material; 
color ;  pulsations ;  thickness  of  walls ;  direction  of  flow  (experiment)  ; 
valves  (experiment). 

Pulmonary  circulation  :  its  purpose  ;  double  structure  of  the  heart ; 
course  of  blood  through  lungs ;  valves  of  heart ;  auricles  and  ventri- 
cles. 

Hepatic  circulation  :  its  purpose ;  blood  from  the  digestive  organs ; 
portal  vein;  passage  of  blood  from  liver  to  heart  and  lungs. 

Lungs  :  situation  ;  structure  ;  trachea ;  bronchial  tubes ;  vesicles  ; 
capillaries. 

Oxygen :  proportion  in  air ;  its  use  to  the  body ;  entrance  into  the 
blood  ;  function  of  red  corpuscles  ;  oxygenation  ;  oxidation  ;  combus- 
tion ;  slow  oxidation ;  changes  in  the  tissues  of  body ;  products  of 
oxidation,  how  disposed  of. 

Temperature  of  body:  the  skin  as  a  cooling  agent;  cold-blooded 
animals;  blushing  and  turning  pale. 

Breathing :  ancient  views  (definitions) ;  mechanical  function  of 
chest ;  its  structure  (experiments  to  illustrate  expansion) ;  how  to 
hasten  inspiration  or  to  make  it  more  powerful.  Diaphragm :  descrip- 
tion ;  shape ;  change  of  shape ;  effect  of  its  action.  Men  compared  with 
women.  Abdominal  breathing:  shallow  compared  with  full  breath- 
ing ;  numerical  data ;  sxDirometer ;  vital  capacity  ;  effect  of  exertion ; 
training  the  chest ;  sympathy  of  the  pulse  ;  rate  of  pulse  and  respira- 
tion; certain  peculiar  forms  of  respiration. 

Taking  cold :  temperature  of  room  and  of  parts  of  body ;  various 
temperatures  preferred ;  effect  of  moisture  in  the  air ;  running. 

Tight  clothing  :  interference  with  breathing,  exercise,  digestion, 
and  circulation  ;  certain  garments. 


CIRCULATION  AND   BESPIBATION.  75 

Asphyxia:  chemical  state  of  the  blood ;  remedies. 

Fresh  air :  when  air  ought  to  be  very  pure  ;  two  sources  of  im- 
purity of  air ;  ventilation,  how  much  required ;  dangers  of  careless 
management. 

Bleeding  :  arterial ;  venous  ;  remedies. 

Fainting  :  cause  ;  remedies. 

Effect  of  alcoholic  drinks  upon  the  skin ;  upon  tlie  pulse  and 
breathing ;  fatal  effects ;  upon  temperature.  Cases  of  exhaustion 
from  fatigue,  etc.  Athletes.  Deceptive  sensation.  Tobacco;  action 
upon  heart  and  circulation  ;  disease  produced. 

l^OTES    FOR   TEACHERS. 

The  lungs  will  be  much  better  understood  if  they  can  be  dissected 
out  of  an  animal  (sheep,  cat,  frog)  in  an  uninjured  state,  and  inflated 
or  blown  up  with  a  pipe  inserted  into  the  windpipe.  It  is  surprising 
how  much  they  enlarge,  —  how  much  larger,  in  fact,  they  are  than  the 
chest  cavit}^,  when  they  are  fully  inflated.  It  will  also  be  perfectl}^ 
plain  that  they  shrink  together  and  become  very  much  smaller  than 
the  chest  cavity,  when  they  are  wholly  empty. 

One  of  the  simplest  exercises  for  developing  the  lungs,  and  one  of 
the  best,  is  the  practice  of  full  breathing.  The  following  is  a  good 
method :  — 

Let  the  windows  be  open  to  a  suitable  extent.  Stand  erect,  head 
up,  back  straight,  facing  the  window.  Do  not  open  the  mouth.  The 
arms  being  at  the  sides,  raise  them  sideways  slowly,  without  bending, 
till  the  hands  touch  over  the  head.  While  raising  the  arms  draw  in 
the  breath ;  take  three  seconds  for  this  operation ;  take  three  more, 
keeping  hands  above  head  and  holdmg  the  breath ;  then  three  more 
to  lower  the  hands  as  slowly  as  they  came  up.  Wait  a  few  seconds 
and  repeat.  Some  persons  become  dizzy  when  they  begin  this  prac- 
tice. They  must  begm  gradually,  not  at  first  taking  so  much  time  as 
directed,  and  not  repeating.  When  accustomed  to  the  practice,  chil- 
dren may  repeat  the  act  six  times  or  more. 

The  chest  and  abdomen  must  be  free,  so  that  no  pressure  is  felt 
from  the  clothes ;  the  collar  loose. 

This  practice  of  full  breathing,  if  carried  out  daily,  will  help  many 
persons  to  avoid  colds  of  the  chest  and  throat.  It  will  also  help  to  get 
rid  of  troublesome  little  coughs. 

A  few  practical  remarks  on  Ventilation  may  here  be  introduced.  — 


76  PHYSIOLOGY. 

The  teacher  should  always  bear  in  mind  that  the  evils  arising  from 
cold  and  draughts  may  exceed  those  caused  by  bad  ventilation.  The 
scholars  will,  however,  generally  bear  a  lowering  of  the  upper  window- 
sashes  for  an  inch  or  two.  If  the  lower  sash  is  raised,  there  should 
be  a  board  set  in  front  of  the  opening  so  as  to  turn  the  current  of  air 
upward. — The  draught  of  an  ordinary  coal  stove  contributes  very 
little  to  the  removal  of  the  close  air  of  a  schoolroom.  The  draught 
of  an  open  fireplace  in  active  operation  is  more  efficient,  though  far 
from  adequate  to  the  needs  of  a  class  of  forty  or  more.  The  flues 
that  are  ordinarily  put  in  for  ventilation  are  usually  absurdly  small.  — 
The  arrangements  for  artificial  ventilation  being  thus  defective,  a 
teacher  often  finds  the  responsibility  of  ventilation  thrown  upon  him 
alone.  If  he  is  willing  to  exert  himself  a  little  in  this  direction,  he 
can  do  nothing  more  practically  useful  than  to  cause  the  scholars  to 
leave  the  room  at  recess,  while  airing  goes  on  ;  and  to  this  he  can  add 
occasional  free  opening  of  the  windows  while  the  class  rise  and  engage 
in  light  gymnastics. 


CHAPTER   V. 

POOD,  DEINK,   AND   DIGESTION. 

CLASSES    OF    FOOD. 

The  foods  used  by  mankind  are  either  animal,  vegetable,  or 
mineral. 

Animal  food  includes  not  only  meat  (in  the  common  sense 
of  the  word),  but  also  the  flesh  of  birds,  fishes,  and  even  rep- 
tiles and  insects.     Eggs,  milk,  and  cheese  are  animal  food. 

Vegetable  food  includes  the  grains,  and  articles  made  from 
grain,  as  bread,  pudding,  porridge  ;  leaves  of  plants,  as  spin- 
ach, lettuce,  cabbage,  dandelion ;  roots  and  tubers,  as  potatoes, 
beets,  turnips ;  the  pith  of  the  sago-palm ;  sugar,  honey,  and 
similar  sweets  ;  oil,  procured  from  olives,  peanuts,  cotton-seed, 
and  many  other  sources. 

Mineral  food  includes  two  very  important  substances,  — water 
and  salt ;  besides  others,  almost  equally  important,  which  are 
not  visible  as  distinct  articles,  but  are  combined  with  other 
foods,  —  as  lime,  potash,  soda,  phosphorus,  iron,  silica. 

This  classification  is  useful  and  convenient,  but  imperfect. 
It  does  not  take  account  of  the  fact  that  each  kind  of  food  can 
be  separated  into  two  or  more  substances  which  differ  greatly. 
Meat,  for  instance,  is  composed  of  fat  and  lean,  which  are 
entirely  unlike.  And,  on  the  other  hand,  the  fat  of  meat  is 
very  like  some  of  the  fats  or  oils  that  are  found  in  vegetables. 
,Such  foods  as  oatmeal  or  maize  contain  several  substances, 
which  the  chemist  separates  and  analyzes.  One  of  these  is, 
chemically  speaking,   like   the  lean  of  meat.      There  is   also 

77 


78  PHYSIOLOGY. 

much  starch,  which  resembles  that  of  the  potato.     Sugar  and 
oil  are  also  found. 

If  we  now  study,  not  the  food  as  it  comes  to  us,  in  a  mass, 
but  the  separate  substances  which  compose  food,  we  find  that 
they  form  four  groups  or  classes,  as  follows  :  — 

1.  Protein  compounds,  or  proteids. 

2.  Fatty  substances,  or  fats  and  oils. 

3.  Carbo-hydrates,  including  starch  and  sugar. 

4.  Mineral  substances. 

Animal  food  is  chiefly  composed  of  classes  1  and  2.  Vege- 
table food  especially  abounds  in  3,  but  contains  all  classes. 

In  explaining  the  uses  and  value  of  the  different  classes  of 
food,  we  will  omit  class  4  for  the  present. 

Class  1  comprises  several  distinct  substances,  among  the 
most  important  of  which  are  albu'min  (represented  by  the 
white  of  eggs),  ca'sein  (by  curd  of  milk  and  cheese),  and 
my'osin  (the  basis  of  lean  meat).  Vegetable  albumin  is  con- 
tained in  wheat  and  other  grains,  in  the  juice  of  most  vege- 
tables, and  in  nuts.  Vegetable  casein  is  found  in  peas,  and 
beans,  and  nuts.  Gluten  is  a  nitrogenous  material  found  in 
grain,  and  composes  the  sticky  part  of  dough.  Associated 
with  these,  yet  not  strictly  in  the  "  proteids,"  are  the  gelat'inous 
substances,  found  in  bones  and  sinews,  and  including  jelly  and 
glue. 

Class  2  comprises  a  great  many  kinds  of  fats  and  oils,  some 
of  which  are  formed  in  plants,  others  in  the  bodies  of  animals. 
The  cream  of  milk,  the  yolk  of  eggs,  the  oil  of  nuts  and  olives, 
are  familiar  examples. 

Class  3  includes  many  sorts  of  sugar,  both  vegetable  and 
animal.  Starch  is  hardly  found  in  animal  food,  but  abounds 
in  vegetable  food  of  almost  all  sorts. 

The  number  of  substances  included  in  these  three  classes  is 
large,  but  they  are  all  formed  by  nature  from  a  very  few 
"simple"  substances,  or  "elements,"  of  which  the  chief  are 
carbon,  oxygen,  hydrogen,  nitrogen,  sulphur,  and  phos'phorus. 

Carbon   is   the    best   known   of    these    elements.      It   can 


FOOD,    BIIINK,    AND   DIGESTION,  79 

be  conveniently  shown  by  holding  any  article  of  food  to  the 
fire  until  it  is  "toasted  to  a  cinder."  The  heat  drives  off 
the  other  elements,  leaving  the  black  carbon  behind. 

Carbon,  hydrogen,  and  oxygen  are  components  of  all  foods 
of  the  first  three  classes ;  but  while  classes  2  and  3  are  entirely 
composed  of  them,  class  1  contains  in  addition  a  fourth  ele- 
ment, nitrogen,  besides  a  very  small  amount  of  sulphur  and 
phosphorus.  Substances  belonging  to  class  1  are  often  called 
nitrog'enous  substances,  while  those  of  classes  2  and  3  are  called 
non-nitrogenous. 

Class  1,  therefore,  contains  all  the  principal  food  elements, 
while  classes  2  and  3  do  not  contain  all.  If  a  person  were 
compelled  to  choose  between  an  absolutely  pure  nitrogenous 
article  and  a  purely  non-nitrogenous  substance,  for  his  sole  food, 
he  would  theoretically  do  better  to  choose  one  of  the  former 
kind.  Fortunately,  however,  we  are  not  required  to  make  such 
a  choice.  In  point  of  fact,  there  are  very  few  kinds  of  food 
which  are  composed  of  only  one  of  these  classes.  ]\Ieat  belongs 
chiefly  to  class  1  (the  proteids),  but  contains  much  of  fat  (2), 
and  even  a  little  sugar  (3).  The  grains  contain  much  starch, 
besides  sugar,  fat,  and  some  of  the  proteids.  Milk  contains  a 
good  proportion  of  each  class.  This  explains  how  it  is  possible 
for  a  person  to  live  in  health  on  one  article  of  food.  Infants  and 
young  animals  thrive  best  upon  milk  alone.  Certain  wild  ani- 
mals live  entirely  on  the  bodies  of  other  animals,  and  there  are 
cases  where  men  have  lived  upon  a  meat  diet  exclusively,  with- 
out the  slightest  injury  to  their  health. 

When  food  is  carefully  selected,  so  as  to  consist  entirely  of 
one  class  only,  it  is  found  that  the  system  camiot  be  supported. 
Lean  meat  and  uncooked  bones  will  certainly  support  a  dog  in 
health ;  but  they  contain  fat  mixed  with  the  other  material. 
Gelatine,  in  particular,  is  unfit  to  support  life  by  itself ;  and 
even  combined  with  other  food  it  is  of  inferior  nutritive 
power. 


80  PHYSIOLOGY. 


PURPOSE   AND    USE    OF    FOOD. 

Food  is  required  for  several  distinct  purposes  :  — 

1.  For  building  up  the  body  and  repairing  its  gradual  waste. 

2.  For  enabling  the  muscles  to  do  work. 

3.  For  producing  heat. 

4.  For  forming  the  secretions. 

5.  For  supporting  nervous  action. 

1.  Growth  and  Repair.  —  Young  and  growing  persons  eat 
comparatively  more  than  grown  persons ;  they  require  more. 
In  later  life,  food  is  not  needed  for  growth,  but  at  all  ages  we 
require  it  to  make  up  for  losses.  Besides  this,  a  constant 
change  is  going  on  in  the  tissues  which  are  already  grown  ;  old 
particles  passing  away  from  the  body,  and  new  ones  entering 
its  structure. 

Chemistry  and  anatomy  inform  us  that  our  bodies  are  com- 
posed of  the  same  substances  that  compose  the  bodies  of  the 
lower  animals.  We  have  muscles,  bones,  skin,  etc. ;  animals 
have  the  same ;  and  for  the  purpose  of  building  up  or  repair- 
ing our  own  substance  we  need  nothing  which  cannot  be  found 
in  ordinary  animal  food. 

But  chemistry  goes  further,  and  informs  us  that  every  sub- 
stance existing  in  our  bodies  can  also  be  made  from  materials 
found  in  vegetable  food.  And  to  this  we  may  add,  as  a  matter 
of  experience,  that  there  are  vast  numbers  of  human  beings 
who  eat  no  animal  food,  or  very  little,  and  yet  are  healthy  and 
vigorous. 

Certain  mineral  substances,  as  lime  and  phosphorus,  are 
especially  required  by  the  bones  and  teeth ;  while  the  brain 
and  nerves  require  phosphorus  and  sulphur. 

2,  3.  Work  and  Heat.  —  A  large  part  of  our  daily  food  is 
used  for  supplying  material  for  working-force  and  for  heat. 
The  way  in  which  food  produces  force  and  heat  is  mysterious ; 
but  we  can  say  that  the  changes  which  it  undergoes,  in 
thus  acting,  are  something  resembling  those  which  we  see  in 
coal  burning  in  a  steam  engine.    That  food  can  burn  is  evident ; 


FOOD,    BRINK,   AND   DIGESTION.  81 

we  need  only  put  it  in  the  fire  to  prove  the  fact.  That  it  can 
burn  in  our  bodies  so  slowly  as  not  to  cause  a  dangerous  heat 
is  not  so  easy  to  comprehend.  Many  readers  may  think  the 
expression  "  chemical  change  "  a  better  one,  or  a  more  intelli- 
gible. At  all  events,  the  food  presented  to  the  system  is  so 
used  as  to  be  chemically  changed,  or  burned ;  and  it  is  by  such 
X^rocesses  that  the  muscles  are  furnished  with  "fuel,"  as  we 
may  call  it,  for  performing  mechanical  labor  or  work. 

The  importance  of  this  function  of  food  is  very  great.  The 
voluntary  muscles  compose  four-tenths  of  the  weight  of  the 
body ;  and  they  have  for  their  sole  duty  the  performance  of 
mechanical  work.  Besides  this,  a  great  deal  of  unseen  labor 
is  performed  by  the  heart,  in  pumping  the  blood ;  and  a  great 
deal  by  the  muscles  of  the  stomach  and  intestines,  in  digesting 
the  food. 

The  muscles,  while  acting,  produce  heat,  as  can  be  proved 
by  careful  measurements  with  the  thermometer;  both  the 
muscles  and  the  blood  being  found  to  rise  in  temperature 
during  active  exercise.  This  fact  shows  the  very  close  rela- 
tion between  work  and  heat. 

The  body,  however,  produces  a  great  deal  of  heat  in  other 
ways,  and  the  presence  of  heat  is  absolutely  necessary  to  life. 

4.  Secretion.  —  Food  is  evidently  required  in  order  to  supply 
the  material  for  forming  the  peculiar  materials  contained  in 
saliva,  the  gastric  juice,  the  bile,  and  other  secretions  (see 
under  "  Digestion  ") . 

5.  Nervous  Action.  —  The  actions  of  the  nervous  system 
have  not  yet  been  described.  They  are  all  bodily  actions, 
and  require  food  for  maintaining  them.  Hence  it  is  certain 
that  our  thoughts,  wishes,  and  feelings,  our  sensations  of 
X:>leasure  and  pain,  our  sight,  hearing,  and  other  acts  of  sense, 
are  all  supported  by,  and  dependent  on,  the  food  we  eat. 

COMPARISON    OF    FOODS. 

The  Effect  of  Different  Kinds  of  Food.  —  It  is  well  known 
that  foods  do  not  act  alike  upon  tlie  body.     A  horse,  for  in- 


82  PHYSIOLOGY. 

stance;  when  fed  with,  oats,  feels  more  spirit  and  goes  more 
willingly.  Dogs  fed  entirely  on  meat  are  made  excitable  and 
often  fierce.  A  moderate  amount  of  meat  has  a  good  effect  in 
making  a  person  active ;  too  much  may  make  one  excitable  or 
irritable,  especially  if  little  exercise  is  taken. 

The  explanation  of  this  effect  of  oats  npon  a  horse  is  the 
fact  that  a  considerable  amount  of  a  certain  nitrogenous  sub- 
stance (gluten)  is  found  in  oats,  very  much  more  than  in  hay. 
It  is  found  in  most  grain,  and  abundantly  in  peas  and  beans. 

The  nitrogenous  substances  found  in  food  are  of  various 
sorts,  but  all  have  a  somewhat  similar  effect. 

The  special  value  of  animal  food  lies  in  its  power  to  excite 
or  arouse  the  body  to  activity  and  vigor ;  this  it  does  more 
potently  than  such  vegetable  foods  as  oatmeal.  Meat  has 
more  power  of  this  sort  than  milk.  Yet  we  cannot  say  that 
animal  food  is  absolutely  required,  though  often  extremely 
useful. 

Several  very  able-bodied  races  of  men  can  be  named  that 
consume  but  little  meat  with  their  food. 

The  Scotch  peasantry  live  mostly  on  oatmeal  (a  stimulating, 
nitrogenous  form  of  vegetable  food)  with  milk.  They  are 
among  the  hardiest  people  in  the  world. 

The  Zulus  of  South  Africa,  who  rank  among  the  bravest  of 
savage  warriors,  support  their  magnificent  muscle  with  milk 
and  cracked  maize. 

The  Arabs,  another  military  race,  live  on  barley  and  camel's 
milk,  rarely  eating  camel's  flesh. 

Milk  is  an  admirable  food,  containing  enough  of  purely 
nitrogenous  matter,  with  much  fat  {i.e.  cream)  and  some 
sugar.  It  is  easily  digested  by  most  persons,  though  some  are 
unable  to  take  much  of  it. 

There  are  some  foods  which  consist  wholly  of  nitrogenous 
materials,  while  others  consist  wholly  of  non-nitrogenous  sub- 
stances. 

Of  the  former  class  are  lean  meat  and  cheese.  Of  the  latter, 
arrowroot,  tapioca,  and  sago  (consisting  wholly  of  starch),  pure 


FOOD,   DRINK,   AND   UIGESTION.  83 

oils  or  fats,  and  sugar.  Pure  starchy  or  sugary  food  by  itself  is 
not  capable  of  sustaining  life  for  a  long  time ;  dogs  thus  fed  die 
of  starvation  in  a  few  days.  Yet  these  foods  are  consumed  in 
immense  quantities  by  the  populations  of  the  world,  and  are 
certainly  of  great  use.  The  body,  however,  does  not  seem  able 
to  put  them  to  practical  use  unless  some  nitrogenous  food  is 
added. 

Hundreds  of  millions  of  people  subsist  mainly  on  rice,  which 
is  almost  pure  starch,  the  chief  addition  made  being  some 
butter  or  other  fat.  Rice,  however,  contains  six  per  cent  of 
proteids,  one-half  as  much  as  wheat  or  maize.  The  potato  con- 
tains a  still  smaller  proportion. 

Value  of  Different  Foods.  —  The  power  of  food,  or  its  value 
in  supporting  life,  depends  on  the  chemical  changes  through 
which  it  passes  in  the  system.  These  changes  are  exceedingly 
complicated,  and  it  is  not  worth  while  to  attempt  to  explain 
them  in  this  book.  There  is,  however,  one  chemical  change 
with  which  all  are  familiar,  —  the  change  which  occurs  in  burn- 
ing. This  process  has  been  used  by  chemists  to  determine  how 
much  effect  the  different  sorts  of  food  produce.  For  this  pur- 
pose they  measure  the  amount  of  heat  produced  by  burning  a 
given  weight  of  different  kinds  of  food. 

When  this  is  done,  it  is  found  that  a  pound  of  fat  gives  out 
in  burning  twice  the  heat  that  a  pound  of  sugar  or  rice  does, 
and  fully  four  times  as  much  as  a  pound  of  lean  beef.  This 
fact  is  believed  by  many  to  prove  that  fatty  foods  stand  far 
above  all  others  in  the  power  to  furnish  force  for  labor.  "  A 
pound  of  wheat  flour  contains  as  much  energy,  to  be  converted 
into  the  heat  which  a  laboring  man  needs  to  keep  his  bod}^ 
warm,  and  muscular  strength  to  do  his  work,  as  two  pounds  of 
lean  beef  free  from  bone ;  while  a  pound  of  very  fat  pork  is 
equal  to  over  four  pounds,  and  a  pound  of  butter  to  nearly  five 
pounds,  of  the  very  lean  beef."  ^ 

Beans  and  peas  contain  a  large  amount  of  nitrogenous  mat- 
ter conjoined  with  starch;  hence  they  are  able,  better  than 
1  Professor  W.  0.  Atwater,  "  Century,"  June,  1887. 


84  PHYSIOLOGY. 

most  other  vegetable  foods,  to  take  the  place  of  meat.  The 
chief  objection  to  them  is  that  they  are  rather  hard  to  digest, 
unless  very  well  cooked.  The  combination  of  beans  with  fat 
pork  —  a  popular  New  England  dish  — has  been  found  by  lum- 
bermen to  be  one  of  the  very  best  foods  for  supporting  severe 
toil. 

Eat,  whether  of  animal  or  vegetable  origin,  contains  only 
three  elements  (carbon,  hydrogen,  oxygen)  ;  and  as  all  these 
are  found  in  starchy  food  and  in  animal  (nitrogenous)  food,  it 
would  seem  that  fat  might  be  formed  out  of  either  class  and 
that  a  man  might  grow  fat  on  a  diet  of  pure  starch,  sugar,  or 
beef.  In  point  of  fact,  pigs  fatten  readily  on  grain.  Barley 
contains  a  small  amount  of  fat,  but  it  has  been  found  by  trial 
that  a  pig  has  "laid  on"  nearly  live  times  as  much  fat  as 
existed  in  the  barley  meal  he  was  fed  with.  In  such  cases,  it 
appears  that  the  system  of  the  animal  has  the  power  of  chang- 
ing a  part  of  the  starch  of  his  food  into  fat.  Hence  persons 
who  are  excessively  fat  are  sometimes  advised  to  eat  very 
little  or  no  starchy  food  (or  sugar,  which  amounts  to  the  same 
thing).  By  this  plan  they  are  excluded  from  bread,  rice,  arrow- 
root, tapioca,  farina,  hominy,  potatoes,  puddings,  cakes,  sugar, 
milk ;  in  fact,  most  of  the  articles  which  make  up  the  bulk 
of  a  meal. 

As  a  general  thing,  children  under  ten  years  of  age  do  not 
require  much  meat ;  milk  is  better  for  them,  and  is  usually 
much  liked.     Above  that  age,  more  ineat  is  desirable. 

An  excess  of  meat  is  often  injurious  to  the  constitution. 
This  and  excess  in  sweetmeats  are  among  the  chief  faults  in 
the  diet  of  Americans. 

Eish  is  commonly  considered  a  "lighter"  food  than  flesh- 
meat  ;  that  is,  less  stimulating.  It  sometimes  agrees  with  the 
stomach  better  than  meat ;  but  there  is  a  wide  difference  in 
fish,  and  some  kinds  are  hard  or  oily,  and  therefore  slow  of 
digestion. 

Eood  that  is  of  itself  very  good  does  not  always  suit  the 
system.     Cheese,  for  example,  though  a  very  valuable  article, 


FOOn,    DBINK,    AND  BIGESTION.  85 

is  in  altogether  too  concentrated  a  form  to  be  eaten  in  large 
quantity.  Its  use  is  to  add  flavor  to  a  meal  of  bread  or  biscuit 
and  at  the  same  time  to  fill  the  place  of  meat.  A  similar  place 
is  taken,  among  the  Spaniards  and  Italians,  by  the  onion. 

Most  food  contains  matter  which  is  not  nourishing,  indigest- 
ible material,  such  as  the  fibrous  or  woody  parts  of  vegetables, 
the  skins  and  seeds  of  berries,  the  branny  part  of  meal.  If  we 
could  get  rid  of  all  such  things,  our  food  might  be  made  more 
delicate,  but  would  not  necessarily  be  more  wholesome.  In 
fact,  the  stomach  seems  to  require  something  to  fill  it  up  to 
a  certain  degree,  more  than  the  mere  nutriment  would  do. 
The  regulation  of  the  bowels  seems  in  many  persons  to  re- 
quire it.  For  this  reason  pulpj^  fruits  and  green  vegetables 
are  wholesome,  as  well  as  coarse  oatmeal,  cracked  wheat,  and 
hasty  pudding,  which  are  not  only  bulky,  but  contain  bran,  a 
material  which  has  a  direct  effect  in  increasing  the  action  of 
the  bowels. 

Certain  kinds  of  food  are  necessary  as  a  preservative  against 
sickness.  The  fare  of  sailors  in  former  times  consisted  chiefly 
of  salted  meat  and  hard  biscuit.  This  can  be  borne  for  a 
while,  but  there  comes  a  time  when  persons  on  such  diet  lose 
strength  and  become  covered  with  sores  ;  they  bleed  much,  and 
if  not  relieved,  die  of  scurvy.  In  the  last  century  ships  and 
even  large  fleets  used  to  suffer  from  scurvy  on  all  long  voy- 
ages, sometimes  to  such  an  extent  as  to  lose  most  of  their  men. 
A  remedy  for  this  scourge  was  put  in  use  by  Captain  Cook, 
who  circumnavigated  the  globe  in  1772-5.  He  provided  his 
ships  with  abundance  of  vegetable  food  and  lime  juice,  and 
obliged  the  sailors  to  use  them.  The  result  was  that  he  lost 
only  one  man  by  sickness  in  the  three  years'  voyage,  and  not 
one  by  scurvy.  At  present  the  practice  is  universal,  and 
scurvy  is  almost  unknown.  When  sailors  are  brought  to 
hospital  with  scurvy,  they  are  fed  with  cabbage,  onion,  potato, 
and  other  vegetables.  Lime  juice,  lemon  juice,  and  the  leaves 
of  sorrel  and  mustard  are  also  very  useful.    The  instinct  which 


86  PHYSIOLOGY. 

teaches  cats  and  dogs  to  eat  grass  and  other  vegetable  matter 
is  doubtless  useful  to  their  health. 

Fresh  meat  is  of  itself  a  good  remedy  for  scurvy.  The  brine 
used  in  putting  up  beef  and  pork  for  sailors'  use  draws  out  a 
large  amount  of  the  nutritious  juices  of  the  meat,  and  so  robs 
it  of  a  great  deal  of  its  value.  Such  meat  has  not  the  health- 
preserving  qualities  of  fresh  meat. 

DRINK. 

Many  kinds  of  drink  are  used  for  quenching  thirst  or  pleas- 
ing the  palate,  but  all  contain  water  as  their  chief  ingredient. 
All  our  food  contains  water,  and  some  kinds  are  little  else. 
The  "juice"  of  meat,  white  of  eggs,  cream,  milk,  custard,  por- 
ridge, jelly,  the  pulp  of  fruits,  are  examples  of  watery  foods. 

We  require  much  water  in  hot  weather  when  working  hard, 
but  in  cool  weather  it  is  possible  to  go  without  drink  if  we 
have  considerable  fruit  and  a  plate  of  soup  at  dinner.  It  is 
not  generally  best,  however,  to  do  without  drink. 

Two-fifths  of  a  person's  weight  consists  of  water.  The 
amount  present  in  the  body  does  not  vary  greatly  from  time 
to  time.  By  running  in  hot  weather  one  may  lose  several 
pounds  by  sweating,  but  that  is  quickly  made  up  by  drink. 
If  a  person  sets  about  it,  he  can  "  train  himself  down ''  to  light 
^veight  by  that  sort  of  exercise  and  by  drinking  less  than  he 
wants.  This  is  done  by  men  preparing  for  racing  and  other 
athletic  contests  in  which  they  desire  to  be  as  light  as  possi- 
ble. Yet  training  does  not  (as  one  might  suppose)  dry  up  the 
body,  but  rather  takes  away  fat ;  for  abstinence  from  drink  is 
one  of  the  surest  means  of  lessening  excess  of  fat. 

Thirst  is  the  craving  of  the  whole  body  for  water.  It  is  felt 
not  only  in  the  mouth,  but  all  over  the  body ;  there  is  a  feeling 
of  weakness,  fatigue,  heat,  and  perhaps  headache,  which  water 
relieves.  Soldiers  marching  in  the  hot  sun  with  gun  and  knap- 
sack are  liable  to  these  sensations,  which,  if  not  relieved,  may 
lead  to  sunstroke.     To  avoid  such  danger,  it  has  been  found 


FOOD,   DRINK,   AND   DIGESTION.  87 

best  in  suck  cases  to  make  the  soldier's  load  as  light  as  pos- 
sible, to  have  the  neck-clothing  perfectly  loose,  to  wear  no 
tight  belts,  and  to  drink  as  much  water  as  is  needed,  —  not  a 
great  quantity  at  once  (which  may  do  harm,  and  at  any  rate  is 
soon  sweated  away),  but  a  little  at  short  intervals,  sipping  it 
slowly.  These  are  the  measures  taken  to  preserve  the  Eng- 
lish troops  in  India  from  sunstroke.  A  wet  handkerchief 
or  a  bunch  of  damj)  leaves  carried  in  the  hat  is  useful. 

Thirst  may  be  a  sign  of  disordered  stomach.  It  is  increased 
by  salt  or  salt  food  or  "hot"  {i.e.  peppery)  food. 

Very  cold  water,  taken  in  large  quantities  when  we  are  very 
hot  and  tired  in  summer,  may  cause  colic,  inflammation  of  the 
bowels,  or  death. 

Ice-water  is  the  favorite  American  drink.  Many  swallow 
large  quantities  of  water  at  about  32°  F.,  and  it  is  thought  that 
this  is  one  cause  why  dyspepsia  is  so  frequent  here.  Xo  other 
nation  uses  it  as  we  do.  It  certainly  disagrees  with  many  per- 
sons, more  especially  at  the  season  when  the  stomach  and 
bowels  are  apt  to  be  delicate  and  easily  "  upset " ;  that  is,  in 
summer.  Some  persons  ought  never  to  drink  very  cold  water, 
^ven  hot  water  is  found  a  suitable  drink  by  some.  For  a 
person  overheated  and  tired  out  a  cup  or  two  of  weak  tea 
is  often  far  more  refreshing  than  a  quantity  of  cold  water. 

Drinking  seems  a  necessity  in  hot  weather ;  but  there  are 
not  a  few  in  whom  simply  drinking  water  brings  on  summer 
complaints.  Such  persons  should  take  little  fluid.  The  car- 
bonic acid  in  effervescing  drinks,  such  as  fresh  soda-water, 
stimulates  the  stomach  and  mouth,  so  that  thirst  is  quenched 
with  a  small  quantity  of  fluid. 

Acid  fruits,  such  as  lemons,  limes,  currants,  the  rhubarb 
plant,  cranberries  and  other  berries,  often  quench  thirst  better 
than  anything  else.  A  little  vinegar  in  water  is  relished  for 
the  same  reason. 

Workmen  in  excessively  hot  places,  such  as  furnaces  for 
smelting  iron,  and  engine-rooms,  require  great  amounts  of 
drink.     In  such  places,  experience  has  shown  that  alcoholic 


88  PHYSIOLOGY. 

drinks  are  not  desirable.  There  is  a  craving,  however,  for 
something  rather  more  nourishing  or  "  sustaining  "  than  mere 
water ;  and  the  craving  is  gratified  by  a  mixture  of  oatmeal 
and  water,  which  in  some  places  is  taken  raw,  in  others  is 
cooked  to  form  a  thin  gruel.  Sugar  and  molasses  are  popular 
in  drink,  doubtless  for  a  similar  reason,  —  because  they  supply 
nutriment  very  quickly. 

AMOUNT    OF    FOOD. 

The  amount  of  food  needed  by  a  person  varies  in  many 
ways.  A  man  requires  a  little  more  than  a  woman ;  growing 
persons  eat  a  good  deal ;  people  recovering  from  fevers  fre- 
quently want  to  eat  the  whole  time.  The  nations  of  the  Arctic 
regions  eat  very  large  rations,  and  white  men  in  those  countries 
do  nearly  the  same,  while  the  people  of  hot  countries  are  mostly 
temperate  in  their  food. 

There  is  a  common  notion  that  it  is  far  better  to  eat  too 
little  than  too  much.  In  America  most  people  have  an  abun- 
dance, and  often  do  eat  too  much;  but  in  Europe  there  are 
millions  of  poor  people  who  would  be  in  better  health  if 
they  could  afford  to  eat  better  food  and  more  of  it.  Meat  is 
used  in  very  small  quantities,  most  country  laborers  eating 
it  but  once  or  twice  a  week.  The  English  navvy  (railroad 
laborer)  uses  much  meat  and  does  a  great  deal  more  work  in  a 
given  time  than  the  French  laborer;  but  experiments  have 
shown  that  a  generous  meat  diet  enables  the  latter  to  do  nearly 
as  well  as  the  Englishman. 

A  small  appetite  is  natural  to  some  persons.  It  is  wrong, 
however,  to  suppose  that  it  indicates  refinement  or  delicacy,  or 
that  it  is  ladylike  to  eat  little.  Girls  need  about  as  much  as 
boys,  and  at  the  age  of  fourteen  (an  age  when  growth  is  very 
rapid)  should  consume  as  much  as  an  average  man.  As  a  gen- 
eral rule  the  appetites  of  children  and  growing  young  folks 
are  a  correct  measure  of  what  their  bodies  require,  provided 
they  have  sufficient  play  and  sleep  and  do  not  pamper  them- 
selves with  candy  and  luxurious  food. 


FOOn,    imiNK,   AND   JJJGESTION,  89 

A  poor  iippetite  may  become  a  habit.  If  a  person  cannot 
eat  breakfast,  the  reason  may  be  want  of  sleep,  anxiety,  heat 
of  the  weather,  over-fatigue,  a  disturbed  stomach  from  im- 
proper food,  or  sleeping  so  late  that  the  stomach  does  not  have 
time  to  wake  up  and  ask  for  food.  The  appetite  can  be 
improved  by  a  short  walk  before  meals,,  not  enough  to  cause 
fatigue.  In  many  cases  of  feeble  health  the  appetite  may  be 
always  poor,  and  the  person  may  have  to  force  himself  to  eat. 

The  habit  of  eating  between  meals  is  generally  injurious,  as 
it  takes  away  the  healthy  appetite  for  meals.  Eating  is  one  of 
the  greatest  of  a  child's  pleasures,  but  the  enjoyment  is  all  the 
greater  when  it  is  reserved  for  certain  regular  times. 

A  short  period  of  abstinence  from  food  may  sometimes  be 
of  great  benefit  to  a  person.  Some  always  eat  too  much,  and 
the  system  cannot  get  rid  of  it  fast  enough  to  keep  in  health ; 
and  sometimes  our  appetite  is  stronger  than  it  needs  to  be,  and 
we  may  get  a  warning,  in  the  form  of  a  headache,  to  give  our- 
selves a  rest. 

HABITS    OF    EATING. 

Times  for  Eating.  —  We  are  not  all  suited  with  the  same 
plan.  Some  persons  eat  but  one  meal  a  day,  even  in  civilized 
countries ;  and  among  the  Guachos  of  South  America,  who  are 
in  the  saddle  all  day,  it  is  the  custom  to  have  but  one  meal, 
consisting  entirely  of  meat,  at  the  close  of  the  day.  In  our 
country  three  meals  is  the  common  plan ;  in  parts  of  Europe 
from  four  to  six  are  equally  common. 

Breakfast  in  America  is  a  solid  meal,  resembling  a  dinner, 
taken  soon  after  rising.  In  Erance  and  Germany  people  take 
a  cup  of  coffee  and  a  piece  of  bread,  which  " stays  the  stomach" 
and  makes  them  feel  able  to  work  till  ten  or  twelve  o'clock, 
when  a  regular  meal  called  "breakfast"  is  taken,  about  three 
hours  after  the  coffee. 

The  benefits  of  a  breakfast  are  plainly  seen  in  the  custom 
followed  in  tropical  countries,  of  never  going  out  of  doors  in 
the  morning  before  taking  a  cup  of  coffee.     This  is  a  very 


90  PHYSIOLOGY. 

great  preventive  of  the  fevers  wMcli  prevail  there.  It  seems 
to  be  a  fact  that  we  take  a  fever  or  a  cold  more  easily  when 
hungry  or  tired  or  weak ;  and  it  seems  also  true  that  in  the 
morning  the  body,  though  rested  in  one  way,  is  not  fully  strong 
until  a  breakfast  of  some  sort  is  taken.  Strength  grows  as  the 
sun  rises  in  the  sky.  We  may  feel  fresh  and  ready  for  any- 
thing at  four  in  the  morning,  but  unless  we  are  used  to  it  we 
shall  find  that  two  hours'  work  at  that  early  time  will  use  up 
our  strength  for  the  day,  unless  we  lay  in  a  supply  of  nourish- 
ment at  the  start.  Most  people  are  strongest  in  the  middle  of 
the  forenoon  or  before  twelve.  Many  students  try  to  work  be- 
fore breakfast,  but  it  is  not  a  safe  practice ;  yet  there  are  some 
who  can  do  it  without  the  least  harm,  for  we  are  not  all  made 
just  alike. 

Dinner.  —  Twelve  o'clock  is  a  common  hour  for  workmen, 
and  a  suitable  one.  For  business  reasons  a  later  hour  is  pre- 
ferred by  many  persons  ;  and  in  the  United  States  it  has 
gradually  grown  later,  until  at  present  six  is  a  very  common 
hour  in  cities,  with  a  lunch  at  twelve  or  one.  A  hearty  meal 
taken  shortly  before  bed-time  is  likely  to  be  injurious  to  young 
children,  preventing  sound  sleep  and  causing  dreams.  They 
should  not  eat  the  family  six  o'clock  dinner,  but  should  have 
a  lighter  repast  of  their  own.  The  use  by  children  of  strong 
tea  or  coffee  at  night  may  be  extremely  mischievous. 

For  children  under  fifteen  it  is  best  not  to  let  more  than 
four  hours  pass,  after  breakfast,  before  taking  lunch  or  dinner. 
A  substantial  dinner  at  noon  is  best.  If  there  is  breakfast  at 
seven  and  dinner  at  one,  there  ought  to  be  a  lunch  between. 
The  morning  is  the  time  when  we  most  need  food,  for  two 
reasons :  first,  because  the  system  has  been  obliged  to  do  with- 
out food  for  twelve  hours,  at  least,  before  breakfast ;  and  sec- 
ond, because  morning  is  the  time  when  a  person  is  expected  to 
do  the  best  and  hardest  work.  Nothing  should  prevent  schol- 
ars and  teachers  from  having  a  solid  and  wholesome  breakfast.^ 

1  These  statements  are  intended  to  apply  to  those  who  follow  the  American 
practice  of  taking  three  meals  a  day.  The  foreign  plan  provides  four,  five,  or 
six  meals,  which,  of  course,  are  comparatively  light. 


FOOD,   BTtTNK,   ANB  DIGESTION.  91 

It  is  a  sign  of  bad  healtk  wlieii  tliere  is  no  appetite  for  that 
meal.  Eating  candy  before  breakfast  is  one  of  the  worst 
possible  habits.  Young  people  must  have  sweet  things ;  but 
they  should  take  them  after  a  meal  of  plain  food.  The  appe- 
tite of  some  children  is  injured  by  drinking  tea  or  coffee. 

Whatever  the  hours  may  be,  we  ought  to  be  regular,  and  not 
eat  between  meals  unless  it  is  necessary.  In  fact,  the  chief 
part  of  what  is  eaten  out  of  meals  is  candy  or  cake  —  eaten  not 
because  we  are  hungry,  but  because  it  tastes  good.  It  is 
natural  to  like  sugar;  well-made  plain  cake  (without  much 
spice)  is  good  for  children  at  proper  times ;  good  candy  (not 
cheap,  not  colored,  not  strongly  flavored)  is  good  at  the  right 
time,  and  that  is,  in  the  place  of  pudding  at  dinner.  Sweets, 
eaten  between  meals,  generally  leave  the  mouth,  in  a  sour 
condition;  some  of  the  sugar  remains  sticking  between  the 
teeth,  and  ferments,  turning  to  an  acid  which  attacks  and  rots 
the  teeth. 

If  sweets  are  eaten,  let  the  tooth-brush  with  soap  be  used 
afterwards.  This  may  seem  needless,  or  "  fussy,"  but  in  truth 
the  mouth  is  often  foul  and  unwholesome  after  such  food,  and 
needs  cleaning  more  than  at  any  time  of  the  day.  Fresh  fruits 
often  contain  sharp  acids,  and  hence  the  same  use  of  a  brush 
may  be  required  after  eating  them. 

Another  excellent  reason  for  not  eating  sweets  between 
meals  is  that  they  spoil  the  appetite  for  solid  food.  A  quarter 
of  a  pound  of  candy  is  not  a  good  thing  if  it  takes  away  the 
appetite  for  a  quarter  of  a  pound  of  beefsteak. 

DIGESTION. 

It  is  evident  that  the  body  of  a  person  is  not  composed  of 
the  things  he  eats.  If  we  examine  the  parts  of  the  body  with 
a  microscope,  we  find  no  crystals  of  sugar,  no  grains  of  starch, 
none  of  the  cells  of  asparagus  or  cabbage  or  apple,  or  any  other 
parts  of  vegetables.  As  for  animal  food,  although  the  muscles, 
bones,  and  other  organs  of  our  bodies  do  resemble  those  of  ani- 
mals which  we  eat,  yet  it  is  certain  that  no  piece  of  any  animal 


92 


PHYSIOLOGY. 


Fig.  41.  — a,  oesophagus;   B,  stomach;    C,  pylo- 


rus; i),  gall-bladder ;  E',  duct  of  pancreas ;  F,  F,  mouth 
small  intestine ;  G,  Cf,  large  intestine. 


food  ever  forms  a  piece 
of  our  bodies.  Food 
has  first  to  be  changed 
to  a  fluid  form,  entirely 
unlike  what  it  had  pre- 
viously.^ The  change 
occurs  in  the  mouth, 
stomach,  and  bowels, 
and  is  called  digestion. 
The  processes  of  diges- 
tion are  performed 
gradually,  and  occupy 
from  half  an  hour  to 
five  or  six  hours.  As 
fast  as  the  food  is 
made  fluid  by  diges- 
tion, it  passes  through 
the  walls  of  the  stom- 
ach or  intestines  and 
enters  the  circulation 
of  the  blood,  whereby 
it  is  carried  to  all 
parts,  and  supplied 
wherever  needed. 

Digestion  can  be  sub- 
divided  into  three 
parts,  corresponding  to 
the  different  regions, 
— ^the  mouth,  the  stom- 
ach, and  the  intestines. 

The  work  of  the 
is    partly   pre- 


1  Note,  as  an  exception,  the  fact  that  fat  and  some  sorts  of  sugar  do  not 
undergo  chemical  change  in  digestion. 


FOOD,   BE  INK,   AND  DIGESTION. 


93 


paratoiy ;  it  cuts,  breaks,  and  crushes  the  food  into  line  parti- 
cles, so  that  the  digestive  juices  may  work  the  better  upon  it. 
In  addition,  saliva  is  mixed  with  the  food,  which  enables  it  to 
be  swallowed  more  easily.  Saliva  oozes  from  certain  glands  ; 
it  is  always  flowing,  but  when  a  pleasant  substance  is  tasted, 
or  something  good  to  eat  is  smelt,  a  larger  fn/'.' ■''"•' '^^ 

quantity  comes,  making  the  mouth  "  water."  ^^;  -^'U 

When  a  person  is  very  tired,  or  anxious,  M-M^ 

or  excited,  the  mouth  is  apt  to  be  dry,  and 
eating  is  unpleasant.  We  cannot  force  the 
fluid  to  come  by  wishing  for  it,  but  we 
may  assist  nature  to  do  so.  Eest  will  help. 
If  one  is  only  thirsty,  drinking  relieves 
the  difficulty,  and  in  a  minute's  time  the 
mouth  becomes  naturally  moist.  While 
the  mouth  is  dry,  it  is  not  fit  to  take 
charge  of  food ;  only  a  very  small  quantity 
can  be  chewed  at  once ;  but  by  beginning 
little  by  little,  the  power  of  producing 
moisture  comes  by  degrees.  To  swallow 
fluid  continually  by  sips  while  eating  is 
exactly  the  opposite  plan,  and  discourages 
nature's  efforts.  (One  of  the  larger  glands 
is  represented  in  Fig.  56.) 

The  office  of  the  saliva  is  not  merely  to 
soften  the  food  so  that  we  can  swallow; 


it   is   a   true  digestive  fluid,   and  has  the 
power   of   changing   the    starch  in  bread. 


Fig.  42. — Gastric  gland 
from  stomach  of  rab- 
bit, highly  magnified. 
1,  tube  through  which 
the  secretion  passes 
into  stomach;  2, 
tube  dividing  into 
branches;  3,  cells  of 
the  divisions,  full  of 
gastric  juice. 


potatoes,  and  other  vegetable  food  to  a  sort 
of  sugar.     Starch  by  itself  is  not  nourish- 
ing till  changed  to  this  sugar.     Little  in- 
fants cannot  digest  starchy  food  at  all,  and  many  die  because 
forced  to  eat  it  mixed  with  milk. 

The  next  part  of  digestion  is  performed  in  the  stomach, 
Avhich  acts  like  the  mouth  in  providing  continually  a  quantity 
of  fluid  to  mix  with  the  food.     Tliis  fluid,  called  gastric  juice,  is 


94 


PHYSIOLOGY. 


poured  out  by  multitudes  of  small  tube-shaped  glands,  situated 
in  the  walls  of  the  stomach  (Fig.  42) .  It  has  the  power  of 
dissolving  the  proteids,  including  the  fibres  of  animal  food. 
Meat  soaked  in  fat  is  protected  by  the  fat  from  the  gastric 
juice,  and  is  therefore  very  slowly  digested. 

Different  sorts  of  animal  food  require  very  different  lengths 
of  time  to  digest. 

Food  not  digested  in  the  stomach  passes  through  a  narrow 
passage,  a  very  little  at  a  time,  to  the  intestines.     The  latter 


Fig.  43.  —  Tubular  glands  from  the  small  intestine  opening  upon  the  mucous 
membrane,  between  the  villi.  Magnified  40  diameters.  The  hilly  surface  is 
the  interior  of  the  intestine,  over  which  the  food  passes;  the  elevations 
(villi,  4,  4)  are  seen  again  in  Fig.  44.  1-1,  representing  the  intestine  where 
cut  through,  showing  a  layer  of  muscles  beneath,  and  the  mouths  of  glands 
above;  2,  glands;  3,  mouths  of  glands. 

form  a  very  long  tube,  winding  and  turning  many  times,  and 
the  food  passes  slowly  and  steadily  through  it,  becoming  mixed 
as  it  passes  with  fluids  coming  from  the  liver,  pancreas,  and 
intestinal  glands.  Here  fats  are  digested,  or,  rather,  are  mixed 
with  a  fluid  which  converts  them  into  an  emulsion ;  -^  and  in 
this  form  they  pass  through  the  walls  of  the  intestine  and  are 
taken  into  extremely  flne  tubes,  called  lac'teals,  which  join  each 
other,  and  at  last  empty  into  the  circulation  of  the  blood. 
The  fluid  which  converts  fat  into  an  emulsion  is  discharged 


1  An  emulsion  is  fat  or  oil  mixed  with  some  other  fluid  and  broken  up  into 
such  extremely  small  globules, that  it  requires  a  microscope  to  see  one.  Salad- 
dressing  is  an  example. 


FOOD,   DRINK,    AND  DIGESTION. 


95 


^ 


i^ 


from  tlie  pancreas.  The  same  fluid  has  a  powerful  action  upon 
starch,  by  which  it  is  converted  into  sugar,  thus  completing  a 
change  only  partially  effected  in  the  mouth.  Proteids  are  also 
digested  by  the  pancreatic  juice. 

There  are,  therefore,  three  kinds  of  digestion,  corresponding 
with  three  great  classes  of  food :  — 

Mouth  digestion,  for  starchy  substances. 

Stomach  digestion,  for  proteids. 

Intestinal  digestion,  for  starch,  proteids,  and  fat. 

The  fourth  class  of  foods,         ^  ^ 
or  minerals,  requires  no  di- 
gestion. 

Water,  and  salt  dissolved 
in  water,  simply  pass 
through   the   walls    of   the  ^" 

mouth,  stomach,  or  intes- 
tines, and  go  thus  un- 
changed into  the  blood. 
When  we  are  very  thirsty,  ^^^ 
water  is  taken  np  with 
amazing  rapidity  by  the  yig.  44, 
stomach.  Certain  poisons 
enter  the  blood  so  rapidly 
that  they  produce  death  in 
a  few  seconds  after  being 
swallowed. 

Pleasant  tastes  and  flavors  stimulate  the  system  in  such  a 
way  that  it  furnishes  the  required  fluids  more  easily ;  they 
therefore  aid  digestion.  But  there  may  be  too  much  of  a  good 
thing,  as  the  boy  found  out  who  was  told  to  eat  all  the  maple 
sugar  he  could. 

The  sensations  called  "  taste  "  are  a  mixture  of  the  feelings 
of  taste  proper  with  those  of  touch,  and  smell.  There  are 
but  few  different  kinds  of  taste,  —  sweet,  bitter,  sour,  alka- 
line, salty.  These  are  perceived  by  the  tongue  chiefly,  and  are 
just  as  distinct  when  the  nose  is  shut.     But  the  peculiar  fla- 


y 


d 


iVo  villi  projecting  into  the 
small  intestine,  magnified  about  50  di- 
ameters, a,  substance  of  the  villus ;  &,  its 
coating  of  cells ;  li^,  detached  cells ;  c,  d, 
artery  and  vein,  Tvith  connecting  capil- 
lary network,  enveloping  and  hiding  e, 
the  lacteal  vessel  which  opens  into  other 
vessels  at  the  base-     ^Diagrammatic.) 


96 


PHYSIOLOGY. 


vors  of  the  oils,  rhubarb,  spices,  fruits,  coffee,  and  many  other 
things,  are  not  noticed  when  the  nose  is  held ;  they  depend  on 
some  volatile  principle  (vapor  or  gas)  which  rises  to  the  nos- 
trils from  the  throat  in  the  act  of  breathing.  The  feeling  of 
softness  or  hardness  of  the  food  is  enjoyed  by  different  per- 
sons. The  hot  taste  of  pepper,  the  cooling 
taste  of  peppermint,  are  still  other  sorts  of 
feelings. 

Spices  have  another  use,  namely,  as  medi- 
cine for  affections  of  the  stomach  and  bowels. 
II  Natives  of  hot  climates   (as  India),  living 

|l  almost  entirely  on  vegetable  food,  are  sub- 

ject to  certain  ill  effects,^  to  remedy  which 
Cayenne  pepper  is  much  used.  Good  cook- 
ing will  do  still  more  to  relieve  the  dif6.culty . 
In  our  climate  we  seldom  require  spices 
for  this  purpose;  they  should  be  regarded 
mainly  as  useful  medicines. 

Salt  is  not  merely  an  article  of  luxury, 
but  is  necessary  for  the  health  of  the  body. 
It  exists  (dissolved),  in  considerable  quan- 
tity, in  the  blood  and  many  other  fluids 
of  the  body.  When  people  are  entirely 
deprived  of  it,  health  suffers,  and  there  is 
Fig.  45. —Mucous    ^   strong  craving  for  it.       It   improves  the 

gland  from  intes-  condition  of  cattle  to  give  it  to  them, 
tine  of  dog.  .       .  . 

Dyspepsia  is  a  name  given  to  a  great 
variety  of  troubles.  The  word  is  Greek,  and  signifies  poor 
digestion.  Some  of  the  common  effects  (or  symptoms)  among 
young  people  are  headache,  sick  stomach,  pain  in  stomach, 
constipation,  bad  breath,  poor  appetite  for  meals,  with  craving 
for  food  between  meals,  dull,  heavy  feelings  of  mind,  ill- 
temper,  and  general  weakness.  It  is  common  among  little 
infants,  owing  to  improper  food,  and  occasionally  causes  their 


1  As  flatulence. 


FOOD,   DBINK,   AND  DIGESTION.  97 

death.  It  is  not  rare  among  children,  often  becoming  an  estab- 
lished habit  which  continues  through  life,  causing  great  suffer- 
ing and  unhappiness. 

The  principal  causes  of  dyspepsia  have  been  given  in  a  few 
words  by  Dr.  William  Pepper  of  Philadelphia  :  — • 

"  In  older  children  the  mastication  of  the  food  becomes  of 
great  importance.  If  this  is  neglected,  gastric  disorder  must 
sooner  or  later  be  induced.  Irregularity  of  meals,  undue  vari- 
ety of  food,  the  premature  use  of  tea,  coffee,  or  spices,  the 
unlimited  use  of  ice-water,  of  fruit,  or  of  sweets,  the  pernicious 
habit  of  eating  candy,  cake,  or  fruit  between  meals,  —  such 
errors  are  responsible  for  a  vast  amount  of  dyspepsia  in  child- 
hood and  for  an  infinity  of  ill-health  subsequently." 

We  cannot  tell  what  kinds  of  food  are  good  for  man  until 
we  have  tried  them.  For  example,  grass  and  leaves  are  excel- 
lent food  for  cattle ;  but  when  tried,  it  is  found  that  man  has 
not  the  power  to  digest  them.  Cattle  are  furnished  with  a 
very  large  apparatus,  consisting  of  several  stomachs,  which 
enables  them  to  digest  such  foods.  In  addition,  cattle  have 
very  large,  broad,  grinding  teeth  (molars),  with  which  they 
are  constantly  chewing  their  food ;  they  have  also  the  power 
of  raising  that  which  is  swallowed,  from  the  first  stomach  to 
the  mouth,  for  the  purpose  of  ''chewing  the  cud,"  and  this 
gives  their  food  a  more  thorough  working  over  than  we  can 
give  to  ours. 

A  great  deal  of  food  can  be  eaten  raw.  Onions,  turnips, 
carrots,  tomatoes,  nuts,  apples,  and  other  fruits  are  examples. 
Many  persons  prefer  them  raw,  while  others  like  them  cooked, 
and  still  others  are  made  ill  by  eating  them  raw.  Some  leafy 
articles,  however,  are  always  eaten  raw,  as  celery,  parsley,  and 
lettuce ;  while  others  are  always  cooked,  as  asparagus. 

Meat  can  be  eaten  raw  without  injury,  unless  it  contains  a 
good  deal  of  connective  tissue ;  in  fact,  the  stomach  digests  it 
more  readily  when  raw.  And  grain,  the  staff  of  life,  can  be 
eaten  raw,  though  it  is  certainly  less  wholesome  so. 

It  is  not  what  we  eat,  but  what  we  digest,  that  nourishes  us. 


98  PHYSIOLOGY. 

And  this  may  remind  us  that  one  person's  stomach  has  no  right 
to  set  up  a  rule  for  another  person's,  for  we  are  not  all  alike ; 
each  of  us  possesses,  it  is  true,  a  stomach,  but  one  person's  may 
be  much  more  able  than  another's  to  do  the  work  it  is  asked  to 
do.  A  delicate  stomach  has  to  be  "  humored  "  by  its  posses- 
sor. It  is  a  misfortune  to  grow  up  with  that  sort  of  stomach, 
for  we  need  the  strongest  and  best  service  from  this  servant  of 
ours,  to  enable  us  to  do  good  work  with  the  whole  of  our 
body. 

The  time  during  which  the  stomach  can  be  made  healthy, 
vigorous,  and  hearty,  is  youth,  —  beginning  with  the  first  day 
of  life  and  going  on  to  adult  age.  The  way  to  do  it  is  for  par- 
ents to  give  suitable  food,  in  proper  quantities,  at  the  right 
times.  A  man  or  woman  thus  brought  up  does  not  have  to 
keep  thinking,  "  What  makes  my  head  ache  ?  or  my  side  ache  ? 
or  why  can't  I  do  my  work  to-day  ?  "  It  is  not  too  much  to 
say  that  one-half  of  the  discomfort,  pain,  and  actual  disease  of 
life  comes  from  putting  things  into  the  stomach  that  have  no 
business  there. 

COOKING. 

Bad  cookery  does  as  much  harm  as  bad  food. 

It  has  been  said  that  "  man  is  a  cooking  animal."  No  other 
creature  possesses  this  art,  and  no  other  needs  it  as  he  does. 
If  he  had  to  depend  on  natural  food,  he  would  be  nearly  con- 
fined to  the  tropics.  There  is  at  present  no  race  so  low  as  not 
to  understand  the  use  of  fire  in  preparing  food. 

Cooking  is  useful  for  several  reasons  :  — 

1.  It  draws  out  nourishing  matter  (gelatine,  fat,  etc.)  from 
the  bones  used  in  making  soup. 

2.  It  destroys  the  life  of  certain  minute  parasitic  creatures 
called  trichin&e,  which  i  are  found  in  the  flesh  of  diseased  pork  ^ 
(rarely  in  other  meat),  and  which,  if  eaten,  cause  severe, 
often  fatal  disease.  In  several  of  our  States  there  are  laws 
which  oblige  those  who  slaughter  swine  to  have  the  meat  ex- 
amined by  an  ofiicial  inspector  with  the  microscope. .    If  the 


FOOD,   BEINK,   AND   DIGESTION.  99 

creatures  are  found,  tlie  pork  is  condemned.  If  pork  is  cooked 
so  as  to  be  "  very  well  done,"  the  lieat  kills  them,  and  the 
meat  is  eaten  without  their  being  perceived,  for  they  are  ex- 
tremely small.  Eating  raw  pork,  or  raw  sausage  made  from 
pork,  can  hardly  ever  be  safe,  though  a  great  many  do  it. 

3.  It  makes  food  taste  better,  —  or  ought  to.  A  good  cook 
can  make  food  attractive  to  the  eye  and  pleasant  to  the  taste ; 
and  a  reasonable  amount  of  sugar,  spice,  and  the  like  condi- 
ments used  for  this  purpose  does  good,  for  it  is  found  by 
experience  that  the  stomach  works  more  willingly  when  we 
give  it  food  in  a  pleasant  way  and  put  it  in  good  humor.  This 
is  of  very  great  importance  for  the  sick  and  invalids,  who 
often  cannot  eat  at  all  unless  things  are  just  right,  and  whose 
life  may  depend  on  the  food  much  more  than  on  the  medicine 
they  take. 

4.  It  gives  warmth.  Most  people  derive  more  benefit  from 
a  warm  meal  than  from  a  cold  one,  except  in  hot  weather. 
Many  drink  hot  water  or  hot  milk  and  water  at  meals  instead 
of  cold  water ;  for  some  this  is  beneficial,  for  others  not. 

5.  Many  different  kinds  of  food  are  mixed  in  cooking. 
This  is  useful  when  not  carried  too  far.  Nature  does  the  same 
in  many  cases :  the  lean  and  fat  of  meat  come  mixed ;  sugar 
comes  in  most  vegetables  united  with  albumen  and  starch; 
flavoring  substances  give  taste  to  the  radish,  the  carrot,  fruits, 
nuts,  grains,  —  in  short,  to  almost  all  natural  food ;  and  that 
excellent  food,  milk,  is  a  natural  mixture  of  sugar,  albumen, 
casein  (cheese),  fat,  and  various  salts.  In  cooking,  therefore, 
it  cannot  be  always  wrong  to  mix  these  substances.  But  we 
learn  by  experience  that  certain  mixtures  may  do  harm,  espe- 
cially when  "  rich  "  or  highly  spiced.  Such  food  makes  one 
feel  heavy  and  stupid,  or  causes  a  burning  or  heat  at  the  stom- 
ach, or  a  sick  lieadache.  A  bad  breath  often  goes  with 
these  symptoms.  Much  of  this  trouble  is  caused  by  the  excess 
of  spice  and  sugar ;  much  also  by  excess  of  fat,  which,  when 
overheated  in  cooking,  is  one  of  the  worst  things  for  the  stom- 
ach.    Butter  is  put  into  cake  and  pie-crust,  and  for  the  first 


lOO  PHYSIOLOGY. 

day  it  may  be  sweet,  but  afterwards  is  apt  to  turn  rancid ;  but 
the  cake  is  eaten  all  tlie  same. 

It  is  natural  to  mix  certain  kinds  of  food.  Very  stimulating 
articles,  such,  as  meat,  are  commonly  eaten  along  with  potato 
and  other  vegetables,  which  are  not  stimulating.  Bread,  and 
articles  made  from  wheat,  barley,  oats,  and  other  grains,  con- 
tain all  the  necessary  ingredients  for  good  food,  but  their 
strengthening  power  is  improved  by  a  little  meat  or  butter,  as 
in  sandwiches,  or  by  adding  milk,  as  for  bread  and  milk.  Oil 
is  similarly  added  to  lettuce. 

6.  The  white  of  an  egg  (called  albumen)  turns  hard  when 
boiled.  This  process  is  called  coagulation.  For  the  easiest 
digestion,  it  is  recommended  that  the  egg  be  eaten  either  beaten 
up  raw  or  else  boiled  full  twenty  minutes.  The  taste  of  the 
consumer,  however,  must  be  consulted. 

Albumen  is  found  in  meat  also,  and  is  coagulated  by  boiling 
or  roasting.  If  the  fire  is  quick  and  hot,  the  outer  layer  of 
meat  is  at  once  made  hard  enough  to  protect  the  inside ;  that 
is,  to  keep  the  juices  from  oozing  out.  Meat  so  cooked  (by 
boiling,  roasting,  or  baking)  will  be  juicy  inside. 

If  we  wish  to  get  all  the  nourishment  out  of  meat  by  boiling, 
to  make  a  soup,  we  cook  it  very  slowly,  hardly  keeping  it  at  a 
boil. 

7.  Cooking  softens  the  fibrous  tissue  of  meat  which  abounds 
in  the  muscles  j  the  effect  is  to  make  the  fleshy  part  of  the 
meat  tender. 

8.  Flavors  are  produced  in  roasting  meat  which  add  to  its 
attractiveness. 

9.  Cooking  is  necessary  for  all  sorts  of  starchy  food,  whether 
made  from  grain  or  from  potatoes,  sago,  etc.  The  hard  grain 
may  be  made  into  soft  flour  ;  but  if  that  flour  is  examined  with 
a  microscope,  it  is  seen  to  consist  largely  of  little  grains  or  cells, 
which  are  solidly  put  together  and  defended  by  coats  which  are 
not  easily  penetrated  by  water.  In  this  condition  the  starch 
can  be  digested,  but  slowly ;  and  it  is  far  preferable  to  soften 
it  first.     When  flour  is  mixed  with  water  and  baked,  or  when 


FOOD,   BRINK,    AND    DIGESTION.  101 

oatmeal  or  rice  is  boiled,  the  starch-cells  absorb  large  quanti- 
ties of  the  water,  and  swell  up  into  a  soft  mass.  Some  kinds 
of  food  cook  in  a  few  minutes,  but  when  the  starch  is  in  a  con- 
dition which  resists  the  process  (as  in  Indian  meal),  it  may  be 
hours  before  it  is  wholesomely  cooked.  Thin  cakes  require 
very  much  less  time  than  loaves,  as  the  heat  does  not  at  once 
reach  the  interior  of  the  latter. 

10.  Baking  and  toasting  partially  change  the  starch  of  the 
outside  parts  to  a  wholesome,  digestible  article  called  malt 
sugar.     The  crust  of  bread  and  the  brown  of  toast  contain  it. 

11.  Light  bread  is  more  wholesome  than  heavy  bread.  The 
lightness  is  procured  by  chemical  means  —  as  by  mixing  saler- 
atus  and  cream-tartar ;  better,  by  yeast ;  better  still,  by  long 
kneading.  The  object  is  to  get  the  bread  full  of  little  bubbles 
of  air,  or  of  some  harmless  gas,  so  that  when  baked  it  may  be 
spongy,  and  easily  mix  with  the  fluids  of  the  mouth.  Bread  or 
cake  that  is  slack-baked,  soggy,  or  doughy,  is  unwholesome, 
for  it  forms  lumps  which  do  not  let  the  digestive  fluids  enter 
and  mix  with  them. 

Even  if  well  baked,  bread  is  often  improved  by  standing  some 
hours,  till  some  of  the  water  has  evaporated  from  it  and  it  has 
lost  some  of  its  softness.  It  is  then  called  ^^  stale."  In  this 
state  it  is  more  wholesome.  Bread  that  will  not  cut  easily  into 
slices  is  too  soft. 

Why  is  pie-crust  complained  of  as  unwholesome  ?  For  sev- 
eral reasons.  It  is  hard  to  make  it  light  and  porous,  as  good 
bread  should  be  ;  the  bottom  crust  is  usually  soggy  and  under- 
done ;  fat  or  butter  is  mixed  with  the  paste  in  a  way  which 
usually  injures  it ;  the  butter  itself  may  be  injured  by  cooking, 
and  it  is  seldom  that  a  delicate  palate  fails  to  notice  a  slight 
rancidity  in  the  crust,  especially  after  it  has  been  kept  some 
time.  G-ood  paste  (a  rare  article)  is  flaky ;  it  melts  in  the 
mouth ;  that  is,  it  is  so  thoroughly  mixed  before  baking  that 
it  quickly  crumbles  and  is  at  once  reached  by  the  fluids  of  the 
mouth. 

12.  The  simple  melting  of  fat   does  not  make  it  unwhole- 


102  PHYSIOLOGY. 

some  J  but  overlieating,  such,  as  occurs  in  frying,  is  apt  to 
make  it  disagree  with  the  stomach.  That  which  drips  from 
roasting  meat  is  mixed  with  browned  flour  to  form  "made 
gravy  " ;  and  this  sort  of  gravy  is  unsuitable  for  many  persons 
to  eat. 

13.  Frying,  when  properly  performed,  improves  the  taste  of 
fish  and  some  other  foods.  It  is  very  injurious  when  so  per- 
formed as  to  allow  the  fat  or  butter  to  soak  in.  To  avoid  this, 
the  fat  must  be  boiling  before  the  article  is  put  in,  or  else  very 
little  fat  must  be  used,  and  a  hot  griddle.  After  frying,  the 
food  may  be  placed  on  paper,  to  soak  away  the  superfluous 
fat.  Boiling  fat  is  so  much  hotter  than  water,  that  frying  is 
done  in  half  the  time  that  is  required  for  ordinary  boiling. 
Frying  is,  therefore,  a  very  quick  and  handy  process.  But  not 
one  cook  in  ten  has  the  skill,  and  is  willing  to  take  the  trouble, 
to  fry  properly;  hence  many  people  object  to  all  fried  food. 


SYNOPSIS. 

Man's  food  is  derived  from  the  three  kingdoms,  —  animal,  vegetable, 
and  mineral :  the  latter  includes  water. 

Food,  as  we  find  it  in  nature,  is  almost  always  a  mixture  of  different 
substances.  If  we  classify  these  substances,  we  find  them  divisible 
into  four  groups,  —  proteids,  fats,  carbo-hydrates,  and  minerals. 

Proteids  comprise  albumin,  casein,  myosin,  gluten :  the  gelatinous 
substances  are  allied  to  them.  These,  and  the  fats,  are  abundant  both 
in  the  animal  and  the  vegetable  kingdom.  Sugar  and  starch  are  char- 
acteristic of  vegetable  lifco  These  substances  are  very  numerous,  but 
are  all  formed  from  a  very  few  elements.  Carbon  (coal),  hydrogen, 
oxygen,  are  found  in  all  foods  of  the  first  three  classes ;  but  class  1 
contains  nitrogen  in  addition,  besides  a  very  little  sulphur  and  phos- 
phorus. 

It  is  very  difficult  to  procure  any  food  which  consists  of  one  of  these 
classes  exclusively.  Meat,  milk,  and  grain  contain  some  of  each  class. 
An  exclusive  meat  diet  is  sometimes  used  without  harm.  But  diet 
consisting  strictly  of  one  class  of  food  does  not  support  the  system. 
Gelatine  is  especially  innutritions  when  exclusively  used. 


FOOD,   nBINK,   AND  DIGESTION.  103 

Food  is  required  for  building  the  body,  for  repairing,  for  muscular 
work,  for  heat,  for  the  secretions,  and  for  nervous  action. 

Young  persons  while  growing  require  comparatively  more  than 
grown  persons.  The  body  can  be  entirely  built  up  from  materials 
found  in  the  bodies  of  other  animals ;  it  can  also  be  built  from  sub- 
stances found  in  vegetables.  Lime  and  phosphorus  are  required 
especially  by  the  bones  and  teeth;  sulphur  and  phosphorus  by  the 
brain  and  nerves. 

Food  is  consumed  or  burned  slowly  in  the  system,  so  as  to  produce 
heat  and  mechanical  force.  The  latter  is  developed  by  the  action  of 
muscles,  both  voluntary  and  involuntary.  Muscular  action  develops 
heat.     Heat  is  generated  in  other  ways  also. 

Secretion  and  nervous  action  are  supported  by  food. 

The  exciting  or  stimulating  action  of  oats  (for  horses),  or  of  meat, 
depends  on  the  presence  of  nitrogenous  material.  Many  foods,  such 
as  maize,  oatmeal,  and  milk,  are  not  classed  .as  specially  stimulating 
foods  for  man,  yet  are  capable  of  sustaining  great  bodily  vigor. 

An  exclusively  nitrogenous  or  non-nitrogenous  diet  will  not  sustain 
the  system.  Yet  many  foods  belonging  exclusively  to  one  class  are 
very  useful  when  combined  with  the  other  class. 

In  undergoing  combustion,  fat  gives  out  much  more  heat  than  sugar 
or  starch;  and  the  latter  much  more  than  lean  meat.  To  some  extent 
this  indicates  the  value  of  these  foods  as  producers  of  force. 

Leguminous  plants  contain  much  nitrogen,  but  their  great  food- 
value  has  the  drawback  of  comparative  indigestibility. 

Fat  in  the  body  can  be  formed  from  starchy,  sugary,  or  nitrogenous 
food.  Starchy  and  sugary  food  may  be  excluded  from  the  diet  of 
obese  persons. 

Excess  in  eating  meat  and  sweetmeats  is  common.  Fish  is  lighter 
food  than  meat.  Some  food  is  too  concentrated  to  be  borne  well  by 
many  stomachs.  Mere  bulk  is  useful  in  the  case  of  certain  indigestible 
parts  of  fruit,  vegetables,  and  grain. 

Scurvy  is  a  poor  state  of  the  blood,  caused  by  deficiency  of  vegetable 
food,  and  by  substituting  salted  for  fresh  meat.  It  affects  sailors  and 
Arctic  travellers ;  in  the  last  centuiT"  it  used  to  be  very  fatal,  but  it  is 
now  understood  to  be  preventible  by  correct  diet. 

Water  is  the  chief  element  of  drink,  and  an  important  one  in  food. 
It  forms  two-fifths  of  the  weight  of  the  body.  Violent  exercise  re- 
moves much  of  it  (in  training).  Abstinence  from  drink  lessens  fat. 
Thirst  is  felt  throughout  the  body.     Sunstroke  may  be  prevented  by 


104  PHYSIOLOGY. 

relieving  thirst,  loosening  the  clothes  of  the  chest  and  neck,  and  carry- 
ing something  wet  in  the  hat. 

Thirst  may  indicate  disorder  of  the  stomach,  or  may  be  unnaturally 
stimulated  by  food. 

An  excess  of  fluid  in  hot  weather  deranges  the  bowels ;  the  effect  is 
worse  if  the  drink  is  cold  (ice-water).  Hot  water,  tea,  effervescent 
drinks,  acidulated  drinks,  and  oatmeal  gruel,  have  their  special  value 
for  many  persons  as  summer  beverages.  Acid  fruits  are  useful  in  the 
same  direction. 

The  amount  of  food  required  differs  greatly  in  different  conditions. 
Generous  diet,  with  meat,  improves  the  working  power.  Growing 
children  require  large  supplies,  and  if  their  food  is  suitable,  they  had 
better  eat  as  much  as  appetite  calls  for.  Poor  appetite  may  spring 
from  disordered  habits  of  living,  neglect  of  exercise,  improper  food, 
or  eating  between  meals.  Occasionally  the  omission  of  a  meal  is  found 
beneficial. 

The  number  of  meals  taken  daily  varies  from  one  to  six,  and  persons 
can  enjoy  health  under  either  plan.  An  early  meal  is  generally  re- 
quired to  give  strength  to  begin  the  day's  work,  or  to  protect  against 
the  noxious  effects  of  weather  or  climate ;  this  meal  may  be  light  or 
full.  Exertion  before  breakfast  should  generally  be  restricted.  In 
simple  life,  dinner  may  well  be  taken  at  noon  :  a  hearty  meal  just 
before  bedtime  is  injurious  to  children.  Children  usually  require 
lunch  four  hours  after  a  meal. 

Eating  between  meals  usually  disorders  the  stomach  or  takes  away 
the  regular  appetite.  If  necessary,  satisfy  appetite  with  plain  food,  not 
cake  or  sweets.    The  teeth  should  be  brushed  after  eating  sweet  things. 

Our  food  mostly  passes  through  chemical  changes  in  digestion.  No 
portion  of  an  animal  or  plant,  consumed  as  food,  exists  as  such  in  any 
part  of  our  bodies. 

Digestion  requires  from  one  to  six  hours,  and  is  accomplished  by 
three  processes,  which  take  place  in  the  mouth,  stomach,  and  bowels. 

In  the  mouth  food  is  cut  and  ground  fine,  preparatory  for  the  work 
of  the  stomach.  Starchy  food  is  partially  digested  in  the  mouth  by 
the  action  of  saliva.  Continual  swallowing  of  liquid  during  eating 
interferes  with  this  process.  Starch  is  feebly  digested,  or  not  at  all, 
in  infancy. 

The  stomach  furnishes  the  gastric  juice  (from  glands  in  its  walls), 
which  dissolves  proteid  substances.     The  time  required  varies  much. 

In  the  intestines  food  is  mixed  with  various  fluids,  of  which  that 


FOOD,    DBINK,    AND  DIGESTION  105 

coming  from  the  pancreas  is  known  as  especially  a  strong  digestive. 
Here  starch  and  proteids  are  further  digested,  and  fats  are  converted 
into  an  emulsion. 

The  products  of  digestion  are  fluids  and  emulsions.  The  former  pass 
into  the  blood-vessels,  which  convey  them  first  to  the  liver,  then  to  the 
heart.     The  latter  enter  the  lacteals  and  are  carried  to  the  heart. 

Tastes  and  flavors  have  their  use  in  stimulating  digestion.  There 
are  few  tastes ;  flavors  are  perceived  by  the  sense  of  smell.  Spices  and 
flavors  have  medicinal  virtues,  and  should  not  be  used  too  much  in  food. 
Salt  is  a  necessity  of  life. 

Dyspepsia  (poor  digestion)  causes  many  troubles  in  young  people, 
and  even  in  infants.  The  chief  causes  have  been  mentioned.  Raw 
food  is  digested  by  animals  more  easily  than  by  man ;  their  stomachs 
are  in  many  cases  formed  quite  differently,  and  their  teeth  enable  them 
to  dispose  of  food  which  we  can  hardly  swallow.  Many  vegetables  can 
be  eaten  raw  ;  tender  meat  is  more  digestible  raw. 

People  differ  greatly  in  their  powers  of  digestion.  Xo  food  nour- 
ishes unless  digested.  Youth  is  the  time  to  lay  the  foundation  of  good 
digestion . 

Cooking  is  practised  by  all  men.     It  has  many  objects  :  — 

1.  Extracting  nutriment  from  bones. 

2.  Destroying  parasites  (trichinae  in  pork). 

3.  Improving  taste,  which  aids  digestion. 

4.  Giving  warmth. 

5.  Mixing  and  combining  food.  Xatm^e  gives  us  the  hint  for  this 
in  many  ways.  In  cooking  we  often  err  in  our  mixtures,  especially 
by  using  an  excess  of  spice,  sugar,  or  fat.  iSTitrogenous  and  non- 
nitrogenous  articles  are  often  properly  combined. 

6.  Coagulating  albumin,  as  in  eggs  and  the  outer  part  of  meat. 

7.  Softening  the  fibrous  tissue  of  meat. 

8.  Developing  flavors. 

9.  Swelling  and  softening  the  grains  of  starch  in  flour,  meal,  pota- 
toes, etc. 

10.  Changing  flour  to  malt  sugar. 

11.  Subdividing  the  mass  of  bread  by  making  it  "  light."  It  is  thus 
easier  to  digest.  Stale  bread  is  wholesome.  Pie-crust  is  unwholesome 
when  heavy  or  stale. 

12.  Fat  overheated  becomes  unwholesome. 

13.  Food  soaked  with  grease  in  frying  is  very  slow  to  digest. 
Quick  frying  in  very  hot  fat  is  recommended. 


106  PHYSIOLOGY. 


■  SUGGESTED   QUESTIONS. 

Various  sorts  of  food :  animal,  vegetable,  mineral.  Why  this  classifi- 
cation is  imperfect.  Chemical  classes  of  food.  Proteids :  some  sub- 
divisions and  examples.  Albumin,  casein,  myosin,  gluten.  Gelatinous 
substances.  Fatty  substances:  examj)les.  Carbo-hydrates.  Ele- 
ments: carbon,  hydrogen,  oxygen,  nitrogen,  sulphur,  phosphorus. 
Mtrogenous  and  non-nitrogenous  food.  Composition  of  meat,  grain, 
milk.    Values  of  certain  diets.     Exclusive  diets. 

Uses  of  food :  growth ;  change ;  origin  of  materials ;  vegetable  and 
animal  materials  for  support ;  mineral  substances.  Work  and  heat : 
steam-engine ;  combustion  of  food ;  fuel  of  muscles ;  amount  of  mus- 
cular work ;  muscular  heat ;  other  sources  of  heat.  Secretion.  iNer- 
vous  action. 

Effects  of  meat,  oats,  hay,  grain,  peas,  and  beans.  Nitrogenous 
food  :  effect :  activity.  Foods  of  certain  races  :  Scotch,  Zulus,  Arabs. 
Milk.  Exclusive  diet ;  combinations.  Rice,  potatoes.  Values  of  foods 
compared;  combustion  giving  rise  to  heat;  compare  fat,  beef,  and 
sugar  or  rice.     Beans. 

Possible  origin  of  fat  in  the  system  from  certain  classes  of  food : 
starch,  sugar,  beef,  grain,  farinaceous  food,  etc. 

Meat  at  different  ages.  Excess  in  certain  articles.  Fish.  Concen- 
trated foods.  Innutritions  material  in  food :  vegetables,  fruit,  coarse 
grains.  Sailors'  fare.  Scurvy:  preventives.  Captain  Cook.  Salt: 
effect  upon  meat. 

Drink:  chief  ingredient.  Watery  foods.  Amount  of  water  in  body : 
diminution ;  exercise ;  fat.  Definition  of  thirst.  Sensations.  Dangers 
and  precautions.  How  to  drink.  Sunstroke.  Causes.  Temperature 
of  water  drank.  Certain  refreshing  drinks.  Carbonic  acid.  Vege- 
table acids.     Furnace  men.     Oatmeal.     Sugar. 

Amount  of  food  required.  Large  eaters.  Poverty.  Meat  for 
laborers.  Needs  of  growing  young  people.  Their  appetites.  Eating 
between  meals.     Abstinence.     Excess. 

Number  of  meals  daily.  Breakfast  in  different  countries.  Value 
of  an  early  meal.  Work  before  breakfast.  Dinner  time.  Length  of 
interval  between  meals.  Late  meals.  Appetite  for  breakfast.  Tea 
and  coffee.     Regularity  of  meals.     Sweets.     The  teeth. 

The  building  of  the  body  from  foods.  Changes  undergone  by  food. 
Digestion.     Time  required.     Kinds  of  digestion.     Mouth  digestion. 


FOOJ),   DBINK,   AND  DIGESTION.  107 

Saliva :  its  office.  Teeth.  Dry  mouth  in  eating.  Drink  taken  while 
eating.     Sipping.     Starch  digestion.     Infantile  digestion. 

Stomach  digestion.     Gastric  juice.     Fat. 

Intestinal  digestion.  Fluids  of  intestine.  Fats.  Pancreas.  Emul- 
sion.    Lacteals.     Starch  and  proteids. 

Absorption  of  water,  salt,  poisons,  etc.  Tastes  and  flavors :  their 
use.  Sense  of  taste ;  of  smell ;  flavors  how  perceived.  Kinds  of 
tastes.  Other  uses  for  flavors  (spices).  Chief  use  of  spices.  Value 
of  salt. 

Dyspepsia:  meaning,  symptoms,  causes.  In  early  life.  Digestive 
powers  of  animals.  Cattle.  Raw  food :  vegetable,  animal.  The 
stomach :  individual  differences,  delicacy,  heartiness ;  how  to  educate 
it ;  value  of  such  education. 

Cooking:  who  employ  it.  Gelatine.  Bones.  Soup.  Parasites. 
Pork.  Slaughtering.  State  laws.  Heat  in  cooking.  Raw  sausages. 
Pleasant  tastes.  Condiments.  Invalids.  Food  versus  medicine.  Cold 
meals.  Hot  drinks.  Mixture  of  foods:  natural;  artificial;  when 
harmful.  What  foods  are  to  be  mixed.  Coagulation.  Eggs.  Cook- 
ing meat:  two  methods.  Softening  fibres.  Flavors  from  roasting. 
Grains  of  starch  :  slow  or  rapid  cooking  required.  Malt  sugar.  Light 
and  heavy  bread.  Stale  bread.  Pie-crust.  Fat  when  cooked  or 
melted.     Gravy.     Frying  :  good  and  bad  way. 


Note.  — The  reader  will  find  no  mention  of  "acoholic  drinks  " 
in  connection  with,  the  chapter  on  Food.  For  an  expression  of 
opinion  by  various  medical  autborities  upon  the  use  of  these 
drinks  as  a  part  of  diet,  reference  is  made  to  Appendix  I.  The 
subject  is  discussed  at  length  in  Chapter  XII. 


CHAPTER   VI. 

THE  SKIN,  OLOTHINa,  AND  BATHING. 

The  skin  consists  of   two  layers,  tlie  epider'mis,  cuticle  or 
scarf-skin^  and  the  der'ma  or  ti^ue  skin,  beneath  the  cuticle. 
If  we  thrust  a  needle  into  the  skin,  a  drop  of  blood  appears 

at   once ;    but  if  we  graze  the 

Fig.  46.  — Skin  of  the  negro,  in  sec-  the  cuticle  is  made  up  of  little 

tion,  magnified  250  diameters.    A,  ,      -,.  mi         n         j.t, 

true  skin;  5,  (7,  Z),  epidermis;    C.  bodies    called    cells  :     those    on 

horny  layer;^i),  deeper  layer  of  ^-^^  outside  are  flat,  those  lying 
epidermis;    D,   layer   of   pigment-  ^  ^      ^ 

cells.   The  projections,  like  fingers,  deeper  are  rounded.    ISTew  cells 
at  A  A   A   are    "papillae"  ;    the  ,       •!       o         •  i.   j-i, 

epidermis  fits  in  between  them.  are   constantly  forming  at  the 

lowest  part,  where  the  cuticle 

rests  on  the  true  skin:    this  increases   the  thickness  of  the 

cuticle,  but,  on  the  other  hand,   a  constant  loss  or  wearing 

away  occurs  on  the  outer  surface,  commonly  in  particles  too 

108 


THE   SKIN,    CLOTHING,    AND   BATHING. 


109 


i^  c 


small  to  be  noticed.  Wasliing  removes  an  outer  layer  of 
cells.  When  the  body  is  soaked  in  warm  water,  —  and  still 
more,  when  it  sweats  freely,  —  these  surface-layers  are  soft- 
ened, and  are  easily 
rubbed  off  in  the  fonn 
of  little  Avhite,  soft  rolls. 

The  outer  layer  of  cu- 
ticle is  called  the  horny 
stratum  or  layer;  man- 
ual labor  makes  it  thick 
and  hard  on  the  palms  of 
the  hands,  and  going 
barefoot  has  the  same 
effect  on  the  soles  of  the 
feet.     (Figs.  46,  47,  C.) 

The  deeper  layer  of 
the  epidermis  (Figs.  46, 
47,  -B,  B)  possesses  a  lay- 
er of  cells  (Z>)  which  con- 
tain coloring-matter.  It 
this    which   gives    to 


IS 


Fig.  47.  —  Section  through  part  of  the  nail 
audits  bed,  highly  magnified.  A,  corium, 
raised  in  ridges,  a,  fitting  in  between 
ridges,  b,  of  tiae  nail;  B,  D,  deep  layer  of 
cuticle ;  C,  horny  layer.  The  letters  cor- 
respond to  those  in  Fig.  46. 


different  races  and  dif- 
ferent individuals  their 
varying  hues  and  complexions,  —  light,  dusky,  tawny,  coppery, 
yellowish,  brown,  black.  Exposure  to  the  sun  increases  the 
pigment  in  a  light  skin,  which  gives  rise  to  "  tanning." 

A  blister  is  formed  by  the  whole  thickness  of  the  epidermis 
becoming  separated  from  the  derma,  and  raised  above  it  by  a 
watery  fluid.  Vaccination  produces  a  kind  of  blister,  prop- 
erly termed  the  vaccine  vesicle;  some  diseases  produce  small 
blisters.  Sunburn  may  cause  blisters,  or  may  only  make  a 
thin  layer  peel  off  the  surface  of  the  cuticle :  a  similar  thin 
layer  comes  off  after  an  attack  of  scarlet  fever. 

The  nails  are  composed  of  cells  belonging  to  the  epidermis 
put  together  more  compactly  than  elsewhere.  The  analogy 
may  be  seen  by  comparing  Figs.  46  and  47.    In  the  next  figure 


no 


PHYSIOLOGY. 


FiGo  48,  —  Section  of  nail  and 
parts  beneath.  1, 2,  4,  horny- 
layer  of  cuticle,  continuous 
with  3,  the  nail;  5,  8,  deep 
layer  of  cuticle ;  9, 12,  derma. 


(48)  it  is  shown  that  the  nail  is  continuous  with  the  epidermis 
of  the  finger.  The  root  of  a  nail  is  the  soft  part,  running  in 
for  a  short  distance  where  the  skin  is  folded  inward.  The  end 
of  the  root,  where  it  starts  to  grow,  is  in  contact  with  true 

skin,  and  the  whole  bed  of  the  nail 
rests  on  true  skin,  so  that,  as  the 
nail  moves  forward  over  its  bed,  it 
grows  at  all  points  at  once,  and  its 
thickness  increases  as  it  approaches 
the  tip  of  the  finger. 

The  hair  is  an  appendage  to  the 
skin,  analogous  to  the  nails ;  like 
them,  it  is  composed  of  compact,* 
hardened  cells,  and  grows  from  a 
portion  of  true  skin.  The  little  pit  in  which  a  hair  stands 
is  called  a  hair-follicle;  the  hair  grows  from  the  bottom  of 
the  pit,  where  it  is  connected  with  the  derma.  Each  follicle 
has  one  or  more  small  seba'ceous  glands  opening  into  it,  from 
which  an  oily  secretion  is  discharged  upon  the  hair.  That 
which  is  not  retained  on  the  hair  spreads  over  the  surface  of 
the  skin.  In  some  parts  of  the  body  (as  the  nose)  the  hairs 
are  very  small,  and  the  oil-glands  very  large  in  comparison ; 
hence  the  oily  appearance  of  those  parts. 

Sweat-glands  consist  of  coiled 
tubes  ending  in  straight  tubes, 
which  discharge  on  the  surface  of 
the  skin ;  the  openings  of  the  tubes 
are  called  ^ores. 

"When  a  hair  or  a  nail  is  pulled 
out,  the  true  skin  at  once  begins  to 
restore  it ;  it  grows  again.  The  same  happens  when  a  piece 
of  cuticle  is  destroyed.  But  if  the  true  skin  is  destroyed  or 
injured,  the  power  of  reproducing  the  skin,  hair^  and  nails  is 
gone.  After  recovery  from  a  deep  burn,  for  instance^  the  scar 
is  not  composed  of  true  skin,  with  epidermis,  but  of  a  whitish 
material,  which  is  strong,  but  is  not  a  very  perfect  substitute 


Fig.  49.  —  Section  of  skin  from 
the  palm  of  the  hand,  nat- 
ural size.  1-1,  epidermis; 
2-2,  papillae;  3-3,  derma; 
4-4,  subcutaneous  cellular 
tissue  and  sweat-glands. 


THE  SKIN,    CLOTHING,   AND   BATHING. 


Ill 


for  skin,  and  has  besides  the  very  great  disadvantage  of  grad- 
ually shrinking,  so  that  the  parts  are  sometimes  pulled  out 
of  shape.  After  a  light  burn  the  skin  may  repair  itself  com- 
pletely in  a  few  days.  Such  an  injury  does  not  prevent  the 
growth  of  new  hair.  A  lost  finger-nail  may  be  replaced  by 
another,  quite  as  good  as  the  first,  if 
the  bed  of  the  nail  is  not  injured. 

The  t7'ue  skin,  or  cutis,  is  much 
thicker  than  the  cuticle.  It  is  some- 
times called  the  coriiwi,  from  the  Latin 
word  meaning  "hide."  From  it  grow 
the  epidermis,  the  nails,  and  the  hair. 
In  it,  as  we  have  seen,  are  found  hair 
follicles,  sebaceous  or  oil  glands,  and 
sweat-glands ;  to  which  we  will  now 
add  nerves  and  blood-vessels. 

As  seen  in  Fig.  51,  the  true  skin 
contains  an  abundance  of  small  arte- 
ries and  veins,  from  which  loops  of 
capillaries  arise,  which  occupy  the 
papillae  or  projections  shown  in  Figs. 
46  and  47.  There  is  an  abundant 
supply  of  nerves  also,  of  which  more 
will  be  said.  The  blood  in  the  true 
skin  shows  readily  through  the  cuticle 
of  the  light-skinned  races.  The  thick- 
ness of  the  cuticle,  however,  differs  in  Fig.  50. 
individuals. 

The  true  skin  is  chiefly  composed  of 
a  tissue  of  strong  fibres,  matted  or 
felted  together  so  as  to  form  a  firm  yet 
pliable  and  elastic  covering  for  the 
body.  In  animals  these  fibres  are  hardened,  by  the  process  of 
tanning,  which  converts  the  true  skin  to  leather. 


Skin,  iu  section, 
enlarged  20  diameters.  1, 
epidermis;  2,  derma;  3, 
hair  follicle,  \\^itli  seba- 
ceous glands ;  4,  rudimen- 
tary hair-follicle;  5,  sub- 
cutaneous tissue ;  6,  sweat- 
gland;  7,  its  duct  of 
discharge;  8,  fat-cells. 


112 


PHYSIOLOGY. 


FUNCTIONS  OF  THE  SKIN. 

The  skin  has  many  functions  and  uses.  Among  the  most 
important  are  those  of :  1.  Protection  j  2.  Sensation ;  3.  Per- 
spiration )  4.  Pegulation  of  the  bodily  temperature. 

1.  Protection.  —  Our  bodies  are  constantly  touching  things. 
If  our  nerves  were  not  covered  over,  every  touch  would  give 
pain,  and  life  would  be  unendurable.  If  the  little  blood-vessels 
were  not  covered  (by  a  cuticle),  the  slightest  rub  against  the 
body  would  set  them  bleeding.     Besides  this^  the  parts  under 


Fig.  51.  —  Papillae  of  the  palm  of  the  hand.  1,  with  two  looped  blood-vessels ; 
2,  with  one  loop  and  one  touch-corpuscle,  9 ;  the  nerves,  arteries,  and  veins 
are  seen  below  (6,  8). 


the  skin  are  soft  and  pulpy,  and  need  the  protection  of  a  drier 
and  tougher  covering,  as  apples  and  other  fruits  require  it. 

2o  Sensation.  —  The  skin  possesses  the  sense  of  touch,  by 
which  we  learn  the  shape,  the  size,  the  roughness  or  smooth- 
ness, and  other  things  about  the  outside  of  objects.  The  skin 
is  therefore  called  the  organ  of  touch,  as  the  tongue  is  the 
organ  of  taste.  The  tips  of  the  fingers  possess  this  power  in 
a  high  degree,  and  are  most  used  for  the  purposes  of  touch. 
The  tip  of  the  tongue  is  nearly  as  sensitive.  Touch  is  per- 
ceived by  means  of  numerous  peculiar,  small,  roundish  bodies, 
the  touch-cor'pusdes,  situated  in  the  true  skin,  just  below  the 
epidermiSo     They  are  found   in  the  papiRse.     (See  Fig.  51.) 


THE  SKIN,    CLOTHING,   AND   BATHING.  113 

The  papillae  are  placed  in  rows,  forming  little  ridges,  and  the 
epidermis  over  them  indicates  the  shape  of  these  ridges,  as 
may  be  seen  at  the  tips  of  the  fingers. 

Other  sensations,  resembling  those  of  touch,  are  felt  by  the 
skin,  as  that  of  ticTding.  The  feeling  of  pain  is  distinct  from 
these.     The  sensation  of  heat  and  cold  is  different  from  either. 

The  sensations  perceived  by  the  skin  may  be  felt  in  other 
parts.  Tickling  is  acutely  felt  in  the  throat ;  when  substances 
get  into  the  windpipe,  the  tickling  becomes  severe  and  pro- 
duces coughing.  The  interior  of  the  mouth  has  a  keen  sense 
of  touch.  Heat  and  cold  are  felt  in  the  mouth  more  acutely 
than  on  the  skin.  Pain  may  be  felt  in  any  part  of  the  body, 
except  in  the  hair,  nails,  or  epidermis.  But  on  the  whole  these 
sensations  are  very  little  felt  in  health,  except  upon  and  by 
the  skin.  The  pain  at  the  moment  a  cut  is  made  is  scarcely 
felt  below  the  skin,  though  after  an  hour  or  two,  when  inflam- 
mation begins,  the  whole  wound  smarts. 

Among  our  commonest  sensations  are  those  of  "feeling 
warm"  and  "feeling  cold.'^  They  may  be  superficial  {i.e.  on 
the  surface  of  the  body)  or  deep.  Every  one  knows  the  feeling 
of  warmth  which  follows  exercise. 

If  we  suppose  this  sensation  represents  the  state  of  the 
interior  of  the  body,  we  have  a  very  wrong  idea ;  there  is  at 
most  but  the  trifling  rise  of  a  degree  or  two  in  the  internal 
heat.  The  true  cause  of  the  feeling  is  the  flow  or  rush  of 
blood  to  the  skin,  caused  by  exercise  5  the  skin  temperature, 
measured  by  the  thermometer,  actually  rises  from  10°  to  20° 
after  exercise ;  and  the  nerves  of  the  skin  take  notice  at  once 
of  the  change. 

Pain  or  discomfort  is  made  of  use  to  us  in  two  ways.  When 
felt  internally  (as  in  the  stomach  or  head  after  eating  impru- 
dently) it  is  a  warning  "  not  to  do  so  again " ;  but  when  felt 
on  the  surface  (from  pressure,  pinching,  burning,  cold,  or  a 
prick,  cut,  or  lash),  it  warns  us  to  stand  out  of  the  way  of 
danger.  The  feeling  of  cold  warns  us  to  put  on  more  clothing; 
that  of  heat,  to  remove  a  part  of  the  clothing ;  and  the  sensa- 


114  PHYSIOLOGY. 

tions  of  the  mouth  often  warn  ns  of  dangerous  food  or 
drink. 

3.  Perspiration.  —  Each  sweat-gland  is  surrounded  by  a  net- 
work of  fine  blood-vessels  (capillaries).  The  blood  contains 
a  large  amount  of  water,  part  of  which  readily  passes  through 
the  walls  of  the  blood-vessels  and  of  the  sweat-gland,  from 
which  it  pours  out  upon  the  surface  of  the  skin.  With  the 
water  there  is  passed  a  little  salt,  which  gives  the  skin  a  salty 
taste  after  perspiring;  also,  some  substances,  partly  vapors, 
and  mostly  unpleasant  to  the  smell,  which  would  be  injurious 
to  health  if  kept  in  the  body.  But  perspiration  consists  almost 
entirely  of  water. 

While  the  sweat-glands  are  actively  at  work,  the  oil-glands 
are  also  in  action,  so  that  the  fluid  covering  the  skin  is  a  mixed 
one. 

There  is  always  a  little  perspiration  coming  from  the  skin, 
except  when  it  is  completely  chilled  and  white.  In  cool  weather 
little  blood  circulates  in  the  skin,  and  the  fluid  upon  the  sur- 
face is  so  small  in  amount  that  it  evaporates  before  it  collects 
in  drops;  tliis  is  called  "insensible  perspiration."  In  hot 
weather,  and  when  exercise  is  taken,  the  blood  flows  freely  to 
the  skin  and  causes  abundant  perspiration. 

The  amount  of  water  which  passes  from  the  body  in  this 
way  is  considerable.  A  man  of  average  size,  at  a  moderate 
temperature  of  the  air,  loses  from  one  to  two  pounds  (pints) 
of  perspiration  daily,  without  perceiving  it.  By  exercising 
vigorously  in  hot  weather,  from  six  to  twelve  pounds  may  be 
discharged.  While  sweating  so  profusely  a  person  feels  hot, 
but  afterwards  there  is  a  feeling  of  great  relief  and  a  cooling 
of  the  whole  system.  . 

Fat  people  often  suffer  from  the  heat.  Vigorous  exercise 
has  a  strong  tendency  to  lessen  the  superfluous  fat,  especially 
if  a  person  drinks  rather  less  than  he  is  inclined  to  do. 


TUE   SKIN,    CLOTHING,   AND    BATHING,  115 


HYGIENE. 

Perspiration  always  contains  some  vaporous  substances 
which,  the  body  needs  to  get  rid  of,  and  which,  as  we  are 
warned  by  the  sense  of  smell,  are  unwholesome  to  breathe. 
These  vapors  are  also  injurious  if  kept  closely  confined  by 
tight-fitting  clothing.  Clothes  ought  always,  but  more  espe- 
cially in  summer,  to  be  made  of  loose  material  to  lWow  the 
vapors  to  escape  freely.  The  use  of  tight  rubber  clothing  is 
most  injurious.  If  the  skin  could  be  completely  covered 
with  rubber  varnish,  death  would  follow  in  a  short  time. 

To  avoid  a  disagreeable  odor  from  the  person, — which  is 
much  more  common  among  "  nice  '^  people  than  they  fancy,  — 
let  the  skin  be  washed  daily  all  over,  using  soap  at  points 
where  odor  is  most  noticed.  Let  it  be  remembered  that  wool- 
len undergarments  are  least  likely  to  take  a  bad  odor  from  the 
body,  while  cotton  or  gauze  ones  are  apt  to  become  offensive 
in  a  day.  The  perspiration  from  the  feet  is  often  unpleasant, 
especially  when  rubber  shoes  are  used.  A  wash  of  carbonate 
of  soda  in  water  may  be  useful  for  this. 

Perspiration  is  often  increased  while  we  are  in  bed.  It  is 
therefore  important  that  the  bedclothes  should  be  thoroughly 
aired  in  the  morning,  the  pieces  being  laid  apart  and  the  win- 
dows opened,  to  remove  the  "  close ''  smell  which  the  clothes 
have,  and  which  is  unwholesome. 

Blankets  and  bedding  which  have  been  used  a  long  time 
ought  to  be  washed.  Such  material  as  cannot  be  washed,  as 
the  cotton  in  bedspreads,  must  be  thrown  away.  It  is  better 
not  to  use  cotton-wool  or  batting  at  all  for  this  purpose,  as  it 
absorbs  the  odors  and  exhalations  of  the  body  and  retains 
them.  Peathers  do  the  same.  For  bedding  which  can  seldom 
be  washed  the  best  materials  are  wool  and  hair ;  wool  for  the 
blankets,  hair  for  mattress  and  pillow.  Cotton  is  suitable  for 
the  washed  clothes ;  linen  feels  cold  to  the  skin,  but  in  hot 
climates  is  a  luxury. 

Attention  to  the  state  of  the  skin  is  required,  not  merely 


116  PHYSIOLOGY. 

for  the  pupose  of  avoiding  offence,  but  for  reasons  of  health. 
Nothing  does  more  for  the  health  of  the  whole  body  than 
good  care  of  the  skin.  A  free,  natural  perspiration  should  be 
produced  every  day  by  exercise,  and  the  products  of  the  per- 
spiration should  be  removed,  with  the  dust,  soot,  and  other 
accidental  matters,  soon  after  exercise. 

An  unwashed  skin  becomes  covered  with  the  substances 
here  mentioned:  the  little  openings  or  pores  become  filled, 
perspiration  is  checked,  and  health  suffers.  What  happens  to 
the  general  surface  of  the  body  may  be  plainly  seen  (in  rather 
a  worse  degree)  upon  the  nose  or  cheeks  of  unwashed  persons ; 
in  those  parts  there  are  large  oil-glands  which  get  choked  with 
their  own  secretions,  and  the  dust  or  soot  of  the  air  getting 
rubbed  into  their  orifices  produces  the  appearance  of  black 
dots.  Erom  these  the  contents  of  the  glands  may  be  squeezed 
in  the  shape  of  something  like  a  grub  or  worm.  Young  per- 
sons, even  when  cleanly,  often  suffer  from  pimples  at  these 
places.  Much  relief  is  got  by  pressing  out  the  "  grubs  "  with 
a  watch-key ;  nor  should  soap  and  water  be  neglected.  Exer- 
cise often  does  great  good.  Medical  treatment  is  sometimes 
necessary. 

At  other  parts  the  orifices  of  the  glands  of  the  skin  are 
liable  to  become  stopped  up,  or  even  grown  over  by  excessive 
growth  of  cuticle. 

The  good  effect  of  attention  to  the  skin  is  often  seen  in  the 
case  of  horses.  A  man  who  cares  for  his  horses,  and  likes  to 
see  them  fresh,  spirited,  bright-eyed,  and  ready  to  go,  will  not 
only  feed  them  well :  he  will  also  see  that  their  skin  is  not 
chilled  by  a  cold  stable ;  he  will  remember  to  blanket  them 
when  standing  in  the  cold;  and  he  will  have  them  ^' groomed^' 
or  rubbed  down  thoroughly  every  day. 

Many  persons  find  it  both  pleasant  and  useful,  after  bath- 
ing, to  rub  the  body  with  a  coarse  cloth  or  a  flesh-brush  as 
hard  as  can  be  borne. 

It  may  be  well  to  add  here,  that  our  toilet  operations  ought 
not  to  be  performed  in  company.     It  is  quite  common,  for 


THE  SKIN,    CLOTHING,   AND  BATHING.  117 

example,  for  young  persons  to  pick  their  teetli  (even  with 
their  fingers),  to  comb  their  hair  with  their  fingers,  to  pick 
their  faces  and  noses  and  ears,  in  the  presence  of  others.  Such 
actions  appear  natural  to  the  one  who  does  them,  but  to  others 
they  are  disgusting,  for  they  suggest  a  dirty  and  neglected 
body. 

The  old  proverb,  "  Dirt  is  wholesome,"  has  wisdom  in  it,  if 
rightly  understood.  Play  in  the  open  air  is  wholesome  ;  chil- 
dren cannot  play  freely  and  vigorously  without  sometimes 
tumbling  on  the  ground.  In  some  of  our  best  games  the 
players  are  liable  to  be  soiled  from  head  to  foot.  But  after 
play  there  is  time  to  wash:  a  dirty  face,  neglected  finger- 
nails, unwashed  neck  and  ears,  frowzy  hair,  or  muddy  clothes, 
will  not  make  a  child  healthier  or  happier. 

In  certain  occupations  workmen  have  to  keep  clean  in  order 
to  avoid  being  poisoned.  For  instance,  workers  in  lead  and 
paint-grinders  are  liable  to  get  particles  of  the  poisonous  dust 
on  their  hands  and  faces,  from  which  it  may  easily  get  into 
their  mouths,  if  they  do  not  wash  before  each  meal. 

Soap  contains  fat  or  oil,  combined  with  an  alkali  (soda  or 
potash).  When  applied  to  the  skin,  its  alkali  dissolves  some 
of  the  grease  of  the  skin  and  softens  some  of  the  top  layer 
of  the  epidermis  ;  the  lather  then  mixes  with  the  dissolved  and 
softened  materials  and  enables  us  to  remove  them  conveniently. 
Soap  also  removes  common  dirt  (dust,  coal,  grease,  etc.)  from 
the  skiuo 

The  skin  can  be  cleansed  of  the  greasy  secretion  by  rubbing 
with  a  dry  cloth.  The  soap,  however,  does  more  thorough 
work,  for  it  dissolves  out  some  of  the  grease  from  the  pores. 
Some  persons  need  to  wash  the  face  with  soap  once  or  twice 
a  day ;  others,  less  frequently. 

Much  of  the  soap  now  sold  is  adulterated  with  materials 
which  do  not  help  in  cleaning.  Much  is  made  with  rancid 
grease,  and  is  injurious  to  the  skin.  Highly  scented  soaps 
may  be  suspected  of  impurity.  There  are  soaps  which  appear 
to  be  very  strong,  owing  to  the  great  quantity  of  soda  they 


118  PHYSIOLOGY. 

contain;  such  strong  soaps  are  not  good  for  the  skin.  Old- 
fashioned  brown  bar  soap  is  not  always  made  of  pure  material. 

The  ancient  Greeks  and  Eomans  were  very  cleanly  in  theii 
habits,  and  very  fond  of  baths.  Instead  of  soaping  the  body, 
they  used  to  rub  themselves  with  sweet  oil,  and  then  cleanse 
the  skin  by  scraping  and  hard  rubbing.  But  before  doing  this 
they  took  som.e  vigorous  exercise,  by  running,  jumping,  dumb- 
bells, ball-playing,  and  in  other  ways,  so  as  to  get  the  skin 
well  covered  with  SAveat;  or  at  least,  they  would  use  a  hot 
bath  long  enough  to  start  the  perspiration,  and  then  would 
wipe,  oil,  and  again  clean  the  skin. 

Good  olive  oil  rubbed  well  into  the  skin  does  not  leave  a 
bad  smell  after  wiping  ;  it  seems  mostly  to  disappear,  for  the 
skin  absorbs  some  of  it,  and  that  which  remains  on  the  sur- 
face can  be  wiped  off. 

Open-air  bathing  is  to  many  one  of  the  chief  pleasures  of 
summer,  and  it  may  be  made  as  wholesome  as  it  is  delightful. 
Sea-bathing  has  some  advantages  over  bathing  in  fresh  water. 
The  water  of  the  ocean  is  peculiarly  stimulating ;  that  is,  it 
seems  to  excite  the  whole  system,  increasing  the  appetite  and 
making  the  muscles  active,  while  the  heart  beats  more  strongly, 
and  the  skin  is  warm  and  glowing ;  and  in  addition  to  this,  it 
puts  the  bather  in  high  spirits,  making  him  want  to  dance  and 
shout.  These  good  effects  do  not  come  at  the  instant  of  enter- 
ing the  water ;  the  first  feeling  is  one  of  cold  and  shrinking, 
which,  however,  soon  passes  off,  and  the  glow  comes  on,  or,  as 
it  is  termed,  the  "  reaction."  In  order  to  promote  reaction,  it 
is  well  to  move  about  vigorously  in  the  water.  Those  who 
react  slowly  or  imperfectly  should  be  very  cautious  about 
bathing,  especially  on  beaches  where  the  water  is  cold.  Some 
persons  are  harmed  rather  than  benefited,  even  by  moderate 
sea-bathing,  the  effect  being  to  make  them  languid  and  feeble. 

We  are  best  capable  of  reacting  at  times  when  we  feel 
strongest,  and  when  the  body  is  well  fed  and  well  rested. 

Before  breakfast  few  persons  can  bathe  in  the  open  air 
without  injury.     The  forenoon,  at  a  reasonable  interval  after 


THE  SKIN,    CLOTHING,    AND  BATHING.  119 

breakfast^  is  the  best  time.  Any  time  when  we  are  very  much 
tired  is  unsuitable.  Immediately  after  a  meal  is  a  bad  time. 
But  a  brisk  walk,  which  does  not  fatigue,  is  rather  a  good  pre- 
paration for  bathing,  only  we  should  not  sit  down  and  cool  off 
before  going  in,  since  "  cooling  off "  may  mean  chilling,  and 
enfeebling  one's  vital  powers.  Extremely  cold  water  is  danger- 
ous for  persons  who  are  over-heated,  and  may  cause  cramps 
with  great  danger  of  drowning,  or  may  bring  on  sudden  and 
fatal  internal  disease. 

It  may  be  weakening  to  stay  in  too  long.  A  good  many, 
however,  do  this,  partly  for  the  pleasure,  partly  for  the  sake 
of  the  company  they  are  in.  Twenty  minutes  is  about  as  long 
as  most  persons  can  stay  in,  and  a  great  many  ought  not  to 
remain  more  than  ten,  or  even  five.  "When  the  water  feels 
decidedly  cold,  the  time  should  be  less.  When  one  has  been 
in  too  long,  he  begins  to  feel  a  little  less  warm,  a  little  tired : 
if  possible,  he  should  come  out  before  he  feels  so.  To  feel 
very  tired  after  bathing  is  a  bad  sign. 

Swimming  is  an  excellent  athletic  pastime,  and  strengthens 
both  muscles  and  wind. 

SYNOPSIS. 

The  skill  is  composed  of  two  layers,  epidermis  and  derma.  The 
latter  only  contains  blood.  The  cells  of  the  cuticle  are  formed  at  its 
deeper  part,  gradually  approach  the  surface,  and  are  at  last  dropped 
or  washed  or  worn  off.  The  outer  layer  of  cuticle  is  the  "horny 
stratum  " ;  the  deeper  layer  contains  coloring  matter.  Blisters  raise 
the  epidermis  from  the  derma :  vaccination  produces  them ;  sunburn 
may  cause  either  blisters  or  peeling  of  the  epidermis. 

The  nails  belong  in  structure  to  the  epidermis ;  the  whole  nail  rests 
on  the  derma.  Hairs  are  analogous  to  nails ;  they  grow  from  derma 
at  the  bottom  of  little  pits  (foUicles) ,  into  which  sebaceous  glands  dis- 
charge. Hairs,  nails,  and  epidermis  are  repaired  or  restored ;  but  if 
the  true  skin  is  destroyed,  these  are  not  restored.  After  deep  burns 
true  skin  is  not  formed,  but  a  tissue  which  shrinks. 

The  cutis  (true  skin)  contains  hair  follicles,  oil-glands,  sweat-glands, 
nerves,  and  blood-vessels.    The  papillae  are  projections  of  the  cutis,  in 


120  PHYSIOLOGY, 

which  capillaries  and  nerve-endings  are  found.  The  fibres  which 
form  the  tissue  of  the  true  skin  can  be  hardened,  by  tanning,  to 
leather. 

The  skin  protects  the  nerves  and  blood-vessels,  and  the  soft  parts. 

It  perceives  objects  touching  it,  and  their  qualities ;  it  is  the  organ 
of  touch,  and  acts  by  means  of  the  touch-corpuscles  in  the  papillae. 
Tickling,  pain,  heat,  and  cold  are  also  perceived  by  the  skin.  Similar 
sensations  may  be  felt  in  internal  parts,  but  the  skin  takes  the  chief 
part  in  their  perception.  The  feeling  of  heat  after  exercise  is  due  to 
the  flow  of  blood  to  the  skin.     Pain  is  a  warning  to  be  cautious. 

The  perspiration  consists  of  water  holding  in  solution  common  salt 
and  other  substances,  some  of  which  are  vaporous ;  it  passes  from 
capillary  vessels  into  the  sweat-glands,  and  thence  to  the  surface. 
The  oil-glands  act  at  the  same  time.  In  cold  weather  there  is  little 
blood  in  the  skin,  and  the  perspiration  is  so  slight  as  to  be  unnoticed 
("insensible  ").  At  a  moderate  temperature  one  or  two  pints  pass  off 
in  a  day,  insensibly :  a  much  greater  amount  during  vigorous  exercise 
in  hot  weather  —  a  practice  tending  to  lessen  fat,  and  give  relief  to 
the  system. 

The  vapor  of  perspiration  ought  to  escape  freely ;  hence  tight 
clothing  is  undesirable,  and  air-tight  clothing  injurious.  Woollen  is 
less  liable  to  become  offensive  than  cotton.  The  bed-clothes  must 
be  aired  to  get  rid  of  perspiration-products.  All  bedding  requires  to 
be  washed ;  cotton  batting,  in  bedspreads  long  used,  has  to  be  re- 
jected ;  and  feathers  after  a  while  absorb  much  from  the  exhalations 
of  the  body. 

Free  perspiration  should  be  sought  daily  by  exercise ;  after  which 
the  skin  should  be  cleansed.  This  frees  the  pores.  Parts  of  the  face 
are  apt  to  show  oil-glands  choked  with  secretion  ("grubs")  and 
pimples ;  cleanliness  partly  relieves  this ;  but  hygienic  and  medical 
treatment  is  often  needed. 

"  Grooming  "  the  skin  improves  the  health  and  spirits  of  man  and 
beast.  A  brisk  rubbing  with  a  coarse  towel  or  flesh-brush  is  invigo- 
rating. Do  not  perform  your  toilet  in  company.  Dirt  got  from 
rough  play  does  no  harm ;  neglected  dirt  does  no  good.  Uncleanly 
paint-grinders  are  liable  to  get  poisonous  particles  into  the  system. 

Soap  dissolves  the  grease  from  the  skin  by  means  of  its  alkali,  and 
helps  remove  it  by  its  lather.  It  does  more  thorough  work  than  a  dry 
cloth.  Much  is  adulterated  with  injurious  material;  some  is  too 
strong  in  alkali ;  perfumes  are  suspicious.  The  ancients  used  oil  and 
liot  water,  with  wiping. 


THE  SKIN,    CLOTHING,   AND  BATHING.  121 

Sea-bathing  is  more  stimulating  than  bathing  in  fresh  water.  The 
first  feeling  is  that  of  cold ;  reaction  gives  a  feeling  of  warmth ;  there 
are  always  some  who  react  poorly,  and  are  liable  to  be  injured  by  the 
bath.  Reaction  is  best  when  we  are  feeling  best :  not  before  break- 
fast, or  when  w^e  are  tired,  or  soon  after  eating.  Very  cold  water 
may  cause  cramp.  The  time  that  persons  can  stay  in  differs  much, 
according  to  their  constitutions. 

SUGGESTED   QUESTIONS. 

Two  layers  of  skin.  True  skin.  Cuticle.  Pricking  with  needle. 
"Barking"  the  skin.  Microscopic  structure  of  cuticle.  Cells:  form, 
point  of  formation,  loss.  Washing,  sweating.  Horny  layer.  Thicken- 
ing. Colored  layer.  Races.  Tanning.  Blisters.  Vaccination.  Scar- 
let fever. 

I^ails  and  hair :  relation  to  cuticle.  Root  of  nail :  bed,  movement 
during  growth.  Hair :  follicle,  relation  to  derma,  oil-glands.  Loss 
of  hair  or  nail.  Destruction  of  true  skin.  Scars.  Burns.  Sweat- 
glands.     Pores. 

Cutis:  thickness.  Structures  contained  in  it.  Blood-vessels.  Pa- 
pillai.     Fibres. 

Uses  of  the  skin.  Protection.  Sensation.  Touch.  What  we  learn 
by  touch.  Where  best  developed.  Organs  of  touch  :  where  situated. 
Papillae.  Various  sensations  like  touch.  Sensations,  as  perceived 
inwardly.     Pain  of  a  cut. 

Feeling  of  warmth  or  cold,  where  perceived.  Relation  of  exercise 
to  this  feeling.  Actual  heat  produced  in  exercising.  Use  or  value  of 
sensation  of  pain,  heat  or  cold,  etc. 

Perspiration :  process  of  its  production,  composition,  mixture. 
Insensible.     Amount.     Effect  of  exercise.     Fat  people. 

Hygienic  value  of  perspiration.  Vapors  of  body.  Tight  or  air- 
tight clothes.  Woollen  vs.  cotton  underwear.  Feet.  Bedding.  Wash- 
ing bed-clothes.  Comparison  of  materials  for  bed-clothes.  Effect  of 
cleanliness,  associated  with  free  perspiration ;  effect  of  neglect ;  pores 
of  face.  Grooming.  Rubbing  down.  "Dirt  is  wholesome."  Lead- 
poisoning. 

Composition  and  action  of  soap.  Adulteration.  Various  ways  of 
cleansing  the  skin.  Oil.  Bathing.  Reaction.  Difference  in  indi- 
viduals. Time  for  bathing.  Cold  water.  Length  of  a  bath.  Swim- 
ming. 


CHAPTER   YIL 

VOICE.  ~  COLDS. 

THE  VOICE. 

The  voice  is  heard  in  speaking  and  in  singing.  It  is  pro- 
dnced  in  the  lar^ynx,  and  its  sound  is  modified  by  the  upper 
throaty  tongue,  palate,  teeth,  and  lips.  To  show  that  it  is  pro- 
duced in  the  larynx,  place  one  or  two  fingers  on  the  side  of 
the  larynx  ('^Adam's  apple"),  and  pronounce  or  sing  a  few 
words  in  a  strong  voice ;  a  thrill  or  vibration  of  the  throat 
is  felt  when  the  voice  is  used. 

The  larynx  is  a  box-like  structure  of  cartilage  at  the  upper 
part  of  the  windpipe.  There  is  at  its  mid-point  a  sort  of  valve, 
which  ordinarily  stands  wide  open,  allowing  the  breath  to  pass 
freely;  but  we  can  when  we  choose  make  the  opening  nar- 
rower, in  which  case  the  air  in  passing  makes  a  noise  like  the 
sound  of  some  musical  instrument.  The  valve  can  be  compared 
to  a  pair  of  half-curtains,  which  usually  stand  apart,  but  can 
be  brought  together  by  the  edges.  The  edges  are  the  vocal 
cords.  When  they  touch,  the  breath  is  prevented  from  pass- 
ing ;  when  separated,  they  leave  between  them  a  narrow  slit, 
called  the  glottis,  in  the  shape  of  a  pointed  oval,  with  smooth, 
clean-cut  edges. 

Every  sound  of  the  voice  has  a  musical  pitch.  The  larynx 
(with  the  throat,  mouth,  etc.)  forms  a  sort  of  musical  instru- 
ment, resembling  an  organ-pipe,  but  with  this  difference,  that 
the  wooden  slit  in  the  pipe  gives  only  one  note,  while  the  lar- 
ynx, by  changing  the  shape  of  the  glottis,  can  give  an  immense 
variety.  High  notes  are  produced  by  drawing  the  cords 
122 


VOICE.  —  COLDS,  123 

tightly,  so  as  to  make  the  glottis  narrow ;  low  notes  Ijy  widen- 
ing the  opening. 

The    motions    of   the  vocal   cords  are  produced  by  several 


Fig.  52.  —  Vertical  section  of  the  mouth,  left  nostril,  and  pharynx.  2,  cartilage 
of  nose ;  8,  cavity  in  the  bone ;  9,  posterior  cavity  of  nostril ;  10,  opening 
of  the  Eustachian  tube;  12,  veil  of  the  palate;  14,  vault  of  the  palate; 
16,  tongue,  forming  the  floor  of  the  mouth;  17,  base  of  tongue;  18,  19, 
20,  muscles;  21,  22,  folds  between  which  (23)  the  tonsil  lies;  24,  tongue, 
where  it  forms  part  of  the  pharynx;  26,  pharynx,  near  larynx;  28,  cavity 
of  larynx ;  29,  points  nearly  to  the  vocal  cords ;  30,  epiglottis ;  32,  thyroid 
cartilage,  cut;  33,  its  upper  border;  35,  36,  cricoid  cartilage,  cut;  37,  mem- 
brane joining  cricoid  and  thyroid  cartilages. 

pairs  of  small  muscles,  which  we  move  without  knowing  it 
though  we  are  conscious  of  intending  to  produce  the  effect. 


124  PHYSIOLOGY. 

Fig.  52  shows  the  upper  respiratory  passages.  The  air,  pass- 
ing from  the  lungs  over  the  vocal  cords  (29);  forms  a  musical 
note ;  the  sound  passes  upward,  and  escapes  freely  when  the 
valve  called  the  epiglottis  (30)  is  drawn  forward.  The  con- 
'nections  of  the  tongue  with  the  larynx  and  epiglottis  are  seen 
to  be  very  close. 

The  Adam's  apple  is  much  more  prominent  in  men  than  in 
women  or  children.  It  begins  to  develop  at  the  time  when  the 
voice  changes  from  the  boy's  treble  to  the  young  man's  bass 
or  tenor.  A  boy  should  not  practise  singing  at  the  period  of 
change ;  it  may  injure  the  voice.  The  average  range  or  compass 
of  women's  and  boys'  voices  is  an  octave  above  that  of  men. 

The  quality  of  the  voice  —  clear,  sweet,  squeaky,  rasping, 
"throaty,"  hoarse,  or  otherwise  —  is  not  due  to  the  larynx 
alone,  but  is  affected  by  the  shape  of  the  pharynx,  nostrils,  and 
mouth.  These  organs  are  partly  well  formed  by  nature,  but 
we  have  some  power  to  change  them  by  voluntary  muscular 
action.  In  training  the  voice,  the  teacher  shows  how  to  hold 
the  parts,  and  by  gradual  practice  accustoms  the  pupil  to  form 
the  throat  and  mouth  into  a  well-sounding  musical  instrument. 
It  is  far  easier  to  do  this  before  the  age  of  twenty  than  after- 
wards. 

Besides  all  this,  a  person  must  have  good  lungs  to  sing  well. 
Singing  is  one  of  the  most  healthful  exercises ;  it  brings  into 
vigorous  activity  all  the  muscles  that  are  used  in  breathing. 
It  also  has  a  favorable  effect  upon  the  circulation  and  digestion. 
In  order  to  sing,  speak,  or  read  well,  a  person  must  hold  the 
head  erect,  must  sit  upright  (or  better,  stand),  and  must  have 
the  body  free  from  confining  garments.  One  should  not  prac- 
tise when  the  throat  is  sore,  or  when  the  stomach  is  full,  or 
when  one  is  very  tired. 

The  voice  is  a  good  test  of  the  state  of  a  person's  health, 
and  a  singer  can  neither  sing  so  high  nor  so  well  when  indis- 
posed. Professional  singers  take  the  greatest  possible  care  to 
avoid  colds,  and  if  they  catch  one,  they  have  it  cured  as 
quickly  as  possible. 


voici:.  —  COLDS.  125 


COLDS. 


The  avoidance  of  colds  is  more  important  than  is  generally 
supposed.  It  is  weakening  to  have  them,  and  it  is  a  sign  of 
weakness  of  constitution  to  have  them  often.  There  are  also 
some  troublesome  and  dangerous  diseases  which  are  brought 
on  by  colds. 

A  "  common  cold "  is  an  inflammation  of  some  part  of  the 
mucous  membrane,  —  that  soft,  red  inner-skin  which  lines  all 
the  air  passages,  and  all  the  food  passages,  and  also  the  middle 
ear,  the  front  of  the  eye,  and  the  cavities  in  the  forehead  bones. 

Sore  throat,  cough,  headache,  fever,  inflamed  eyes,  deafness, 
loss  of  taste  and  smell,  diarrhoea,  want  of  appetite,  and  aches 
all  over  the  body  are  well-known  symptoms,  noticed  at  differ- 
ent times.  Many  are  so  affected  by  a  cold  that  they  are 
unfit  to  be  out  of  bed.  Influenza  is  a  severe  sort  of  cold  which 
attacks  large  numbers  of  persons  at  once. 

Deafness  is  sometimes  present  in  case  of  a  cold.  If  the  per- 
son recovers  completely,  the  deafness  passes  away ;  but  if  the 
throat  remains  more  or  less  sore,  the  ear  trouble  is  apt  to  con- 
tinue, and  thus,  by  degrees,  many  persons  become  deaf.  Ear- 
ache, a  severely  painful  affection,  is  often  due  to  a  cold  which 
affects  the  middle  ear. 

The  eye  is  covered  in  front  with  a  delicate  mucous  mem- 
brane, which  also  lines  the  lids.  It  can  easily  be  seen  by  turn- 
ing back  one  lid.  Wlien  dust  gets  into  the  eye,  the  membrane 
becomes  reddened.  Dust,  wind,  and  a  cold  in  the  head  often 
cause  injlammation  of  this  membrane,  or  "  a  cold  "  in  the  eye. 
The  tear  passage,  which  connects  the  eye  with  the  nose,  is 
often  the  channel  by  which  a  cold  travels  up  into  the  eye. 

An  exposure  to  cold,  which  in  our  northern  climates  causes 
a  cough,  is  apt  in  hot  countries  to  cause  a  disease  of  the  liver 
or  bowels.  Some  very  painful  and  fatal  affections  of  the 
digestive  organs  are  caused,  in  hot  countries,  by  carelessly 
sitting  down  in  a  draught  to  "cool  off  when  overheated;  and 
the  same  may  occur  in  the  heat  of  our  own  summer. 


126  PHYSIOLOGY. 

One  cold  often  makes  a  person  the  more  liable  to  take 
another,  for  it  leaves  a  person  somewhat  weaker  and  more 
^'  tender  "  ;  or  else  it  may  not  be  wholly  cured,  and  may  lurk, 
ready  to  break  out  again,  in  some  corner  of  the  throat,  ear,  or 
nose.  Some  seem  always  to  have  a  cold,  or  to  be  just  going 
to;  while  others  scarcely  ever  have  one,  and  if  they  do  it 
passes  off  in  a  day  or  two. 

Consumption  not  infrequently  begins  with  a  severe  cold, 
which  is  allowed  to  run  on  uncured  for  weeks  or  months.  The 
two  diseases  are  not  the  same  ;  but  the  cold  may  lay  the 
foundation  for  the  more  serious  complaint.  In  other  persons 
the  lungs,  after  such  long  colds,  become  permanently  delicate, 
and  will  not  endure  to  breathe  the  out-door  air  at  night; 
they  acquire  a  chronic  bronchitis.  The  measures  which  are 
useful  in  enabling  people  to  resist  colds  are  also  useful  in 
preventing  consumption. 

A  chronic  (or  continuous)  sore  throat  often  plagues  those 
who  speak  much  in  public.  It  is  largely  due  to  their  using 
the  voice  in  a  strained,  unnatural  way.  It  is  not  so  likely  to 
be  produced  by  speaMng  as  by  reading.  But  practice  in  read- 
ing aloud,  under  good  instructors,  is  beneficial  to  both  throat 
and  lungs  ;  like  other  exercise,  it  ought  to  be  continued  nearly 
every  day,  and  ought  to  be  very  moderate  at  the  beginning ; 
though  by  practice  a  person  may  be  able  to  read  for  hours. 
Singing  is  much  harder  work  than  speaking  or  reading.  It  is 
very  beneficial  when  performed  correctly  and  with  an  avoid- 
ance of  false,  strained,  unnatural  efforts.  It  is  a  great  art  in 
a  teacher  to  enable  a  i)upil  to  sing  or  read  easily. 

Among  the  chief  causes  of  colds  are  exposure  to  cold,  to 
dampness,  to  draughts  of  wind,  to  sudden  changes  of  temper- 
ature ;  improper  clothing  is  also  a  cause.  Instances  are : 
going  from  a  warm  room  to  sit  in  a  cold  one,  or  into  a  chilly, 
unwarmed  hall;  sleeping  between  sheets  that  are  not  thor- 
oughly dried;  sitting  in  wet  clothes  or  damp  stockings; 
changing  from  thick  to  thin  clothes  too  early  in  spring.  Too 
thick  clothes  indoors,  in  hot  rooms,  make  persons  "  tender,''  or 


VOICE.  —  COLDS.  127 

liable  to  take  cold.  A  hot,  dry  room  may  bring  on  a  cold  in 
the  head. 

"The  heads  of  some  children  are  oftentimes  vigorously 
washed  without  being  thoroughly  dried;  they  are  allowed  to 
remain  in  water  unduly  long ;  their  arms  and  chest  are  left 
uncovered  in  weather  in  which  strong  men  are  clad  in  beaver- 
cloth  and  women  in  furs ;  they  play  about  the  streets  and  sit 
down,  when  tired  and  warm,  on  the  damp,  cold  stone  steps  of 
ci!;y  houses  ;  they  are  held  thoughtlessly  by  open  windows  on 
a  cold  day;  they  are  warmly  clad  by  day,  but  insufficiently 
covered  by  night."  ^ 

The  dress  of  women  is  often  quite  insufficient  to  keep  them 
warm. 

Those  who  live  entirely  in  the  open  air  by  day  and  night,  in 
a  pleasant  climate,  are  usually  free  from  colds.  The  open  air 
is  one  of  the  greatest  strengtheners  of  the  system.  Even  in 
bad  climates,  like  that  of  the  Atlantic  States  in  winter  and 
spring,  it  is  best  to  spend  a  great  deal  of  time  out  of  doors ; 
two  hours  a  day  if  possible,  and  much  more,  if  convenient,  on 
most  days. 

The  sunshine  and  dry  air  are  good  — •  fog,  damp,  high  winds, 
and  dust  are  bad  — •  for  those  who  take  cold  easily.  Plenty  of 
good  food  and  exercise  are  good ;  loss  of  sleep  and  overwork 
are  bad.  If  a  person  can  bear  a  daily  cold  sponge  bath  (and 
most  can),  it  will  lessen  the  delicacy  or  tenderness  of  the  skin, 
and  enable  him  to  resist  cold  better.  The  weaker  parts  (as 
the  throat,  in  some  persons)  should  especially  be  thus  bathed. 
Very  pure  air  in  the  house  is  desirable.  The  temperature  of 
62°  to  65°  F.  is  probably  the  best  for  houses,  and  70°  should  be 
a  maximum.  Our  houses  in  America  are  usually  kept  too 
warm  in  winter,  which  makes  our  countrymen  delicate.  The 
Europeans  are  comfortable  at  60°,  or  a  little  above  it. 

The  systematic  practice  of  deep  breathing,  as  described  on 
page  76,  is  most  useful,  both  as  preventing  colds  and  as  devel- 
oping the  voice. 

J  Dr.  St.  John  Roosa, 


128  PHYSIOLOGY. 

Many  physicians  recommend  that  the  body  should  be 
clothed  in  soft  flannel  from  head  to  foot  at  all  seasons.  Some 
persons  find  their  health  much  benefited  by  this  plan ;  it  is  a 
preservative  against  rheumatism  and  colds.  Others,  however, 
appear  to  be  sufficiently  robust  not  to  need  flannels  at  all.  In 
this  respect,  as  in  many  others,  there  is  great  difference  in 
individuals. 

Many  delicate  23ersons  cannot  use  cold  baths,  but  are  bene- 
fited by  warm  baths.  The  water,  in  such  cases,  must  be  warm 
enough  to  feel  comfortable,  and  the  room  must  also  be  warm. 
Such  persons  cannot  bear  cold  weather  well. 

The  "  Turkish  bath ''  requires  an  extremely  hot  room,  in 
which  people  sit  and  sweat  for  a  while,  and  then  are  rubbed 
down  with  soap  and  hot  water,  after  which  they  jump  quickly 
into  a  tank  or  pond  of  cold  water  for  a  few  seconds.  The  cold 
water  prevents  taking  cold  after  the  bath.  The  Eussians  have 
the  room  full  of  hot  steam;  and  when  they  have  sat  long 
enough,  they  run  out  and  jump  into  snow  or  icy  cold  rivers. 
This  would  be  a  little  too  violent  for  us. 

The  Turkish  bath  is  a  good  preventive  of  catarrhs  or  colds. 
Those  persons  who  are  subject  to  head  colds  or  affections  of 
the  ear  may  omit  the  cold  plunge  and  the  shampooing  of  the 
head. 

SYE^OPSIS. 

The  voice  is  produced  in  the  larynx  and  modified  in  the  upper  air 
passages.  The  sound-producer  consists  of  the  edges  of  the  two  thin 
curtains  (cords)  which  vibrate  while  the  air  rushes  through  the  slit 
between  them  (called  the  glottis).  The  tension  of  the  cords  and 
shape  of  the  glottis  can  be  changed  by  muscular  action,  producing 
different  musical  notes.  The  epiglottis  protects  the  larynx  from  the 
entrance  of  substances  in  swallowing.  While  the  voice  is  changing 
and  the  Adam's  apple  enlarging,  boys  should  not  sing  much. 

The  quality  ("timbre")  of  the  voice  is  affected  by  the  pharynx 
and  parts  adjacent.  In  training  the  voice  one  learns  to  hold  the  parts 
correctly. 

Singing  is  very  wholesome.     The  dress  in  singing  must  be  easy,  the 


VOICE.  —  COLDS.  129 

posture  erect,  the  body  free  from  fatigue  or  illness,  and  the  stomach 
not  full. 

Colds  are  ^veakening,  and  often  dangerous.  They  consist  of  in- 
flammation of  the  mucous  membranes  of  various  regions,  with  many 
symptoms,  chiefly  of  the  resj)iratory  and  digestive  organs,  eyes,  and 
ears.  Deafness  often  originates  in  colds.  The  liver  and  bowels,  in 
hot  countries,  are  often  affected  where  the  respiratory  organs  would 
be  in  cold  countries. 

One  cold  prepares  the  way  for  others ;  or  even  for  chronic  bronchitis, 
or  consumption.  Chronic  sore  throat  may  be  due  to  improper  use  of 
the  voice. 

The  causes  of  colds  include  chills,  draughts,  improper  clothing,  and 
excessive  heat  of  rooms.  Life  in  the  open  air,  sunshine,  dry  air,  cold 
washing  or  bathing,  cool  rooms,  practice  in  deep  breathing,  and  things 
which  strengthen  the  system,  help  to  prevent  colds.  Flannels  and 
Tm'kish  baths  are  useful  to  manv. 


SUGGESTED  QUESTIOXS. 

Yoice :  production,  modification.  Vibrations.  Larynx.  Vocal 
cords.  Glottis.  Musical  pitch.  Muscles.  Epiglottis.  Development 
in  boys.  Adam's  apple.  Quality  of  tone.  Training.  Singing : 
effects  ;  conditions  to  be  observed  in  practice. 

Colds.  Definition.  General  symptoms.  Ear.  Eye.  Digestive 
organs.  Late  effects  :  disease  of  lungs ;.  chronic  sore  throat.  Causes  : 
"  exposm-es  "  of  many  sorts,  heat,  cold,  dampness  ;  injudicious  manage- 
ment of  children.  Preventives ;  air,  climate,  bathing,  temperature, 
lung-exercise,  clothing. 


CHAPTER   VIII. 

THE   NEEVOUS   SYSTEM. 

We  have  seen  how  the  body  and  the  members  are  made  to 
move;  that  is,  by  the  muscles.  The  heart  contracts  (beats) 
because  it  is  a  muscle.  The  blood-vessels  are  encircled  with 
minute  muscles,  which  aid  in  propelling  the  blood.  The  stom- 
ach and  bowels  have  much  muscular  fibre,  with  which  the  food 
within  is  pushed  onward.  Besides  these  functions,  there  is 
the  very  important  one  of  breathing,  which  is  dependent  on 
muscular  action.  But  muscles  of  themselves  will  not  do  work. 
They  require  to  be  ordered  and  guided  and  regulated,  and  this 
is  the  duty  of  the  nervous  system. 

Man  is  also  endowed  with  what  is  vulgarly  called  his  "  seven 
senses  "  or  "  seven  wits  "  ;  they  are,  in  reality,  five,  —  sight, 
hearing,  smell,  taste,  and  touch.  All  these  depend  on  the 
nerves,  each  sense  having  an  organ  with  a  peculiar  structure, 
which  belongs  to  the  nervous  system.  All  j)ain  and  all  pleas- 
ant sensation  depend  on  the  nerves. 

The  brain  also  —  the  organ  of  the  mind  —  is  a  part  of  the 
nervous  system. 

Finally,  the  secreting  power  of  all  the  glands,  from  the  liver 
down  to  the  little  sweat-gland,  is  under  the  control  of  nervous 
influence. 

The  nervous  system  is  thus  seen  to  be  connected  with  four 
of  the  chief  functions  of  life,  —  those  of  thought,  sensation, 
motion,  and  secretion.  It  has  the  entire  control  (so  far  as  the 
body  has  anything  to  do  with  it)  in  the  case  of  thought  and 
sensation.  It  has  the  regulation  and  direction  in  the  case  of 
motion  and  secretion. 

The  nervous  system  in  a  man  may  be  compared  to  the  gen- 
130 


THE  NEEVOUS   SYSTEM. 


131 


eral  of  an  army,  with  his  officers  and  scouts.  He  himself  is  the 
brain ;  he  alone  knows  what  has  been  done,  and  Ayhat  is  to  be 
done.  His  scouts  and  sentries  are  his  nerves  of  sight,  hearing, 
and  feeling.  His  officers  are  the  nerves  of  motion,  conveying 
orders  to  the  regiments  and  companies,  —  the  muscles.  His 
commissary  agents  are  the  nerves  regulating  the  glands  and 
stomach. 

It  is  easy  to  see  that  the  nervous  system  is  the  highest  part 
of  the  bodily  frame. 

ANATOMY. 

The  nervous  system,  as  a  whole,  is  chiefly  built  up  of  fibres 
and  cells,  both  of  which  structures  are  so  small  as  to  require 


Fig.  53.—  Section  of  part  of  the  spinal  cord.  A,  A,  bundles  of  nerve-fibres; 
B,  B,  C,  the  same,  dividing  into  separate  fibres;  D,  circles  showing  nerve- 
fibres,  cut  across  ;  E,  nerve-cells. 

a  microscope  to  see  them.  Cells  are  commonly  found  in  great 
numbers  together ;  and  fibres  are  usually  united,  many  together 
in  one  bundle  or  hank,  forming  what  looks  like  a  white  thread. 
One  such  bundle  is  what  is  commonlj^  called  "a  nerve.'^ 

A  mass  of  nerve-cells  has  a  pinkish  gray  color,  as  ma}^  be 
seen  by  examining  the  surface  of  an  animal's  brain,  the  outer 


132  PHYSIOLOGY. 

layer  of  which  is  composed  of  such  cells.  Such  a  mass  is 
called  gray  matter.     A  group  of  cells  is  a  ganglion. 

There  is  much  variety  in  the  forms  of  the  cells,  but  each 
consists  of  a  little  sac  or  bag,  filled  with  a  peculiar  chemical 
substance  containing  much  phosphorus,  A  small  body  called 
the  nucleus  (kernel)  is  found  in  the  interior.  Cells  have  one 
or  more  branches  j  to  some  of  the  branches  nerve-fibres  are 
attached. 

The  nerves,  outside  of  the  brain  and  spinal  cord,  contain  no 
cells.  They  are  supported  (being  delicate,  soft  structures)  by 
strong  sheaths  of  white  fibrous  tissue. 

The  nervous  system  can  be  divided  into  two  parts.  One  of 
these,  —  including  (a)  the  brain,  (b)  the  spinal  cord,  and  (c)  the 
nerves  which  belong  to  the  muscles,  skin,  and  organs  of  sense, 
—  is  called  the  cerebrospinal  system,  or  division  of  the  nervous 
system.  The  other  division  belongs  chiefly  to  the  internal 
organs  and  the  circulation,  and  is  called  the  visceral  system : 
it  will  not  require  much  of  our  attention. 


CEREBRO-SPINAL  SYSTEM. 

The  brain  fills  the  entire  cavity  of  the  skull ;  not  merely  the 
forehead  part,  but  also  the  parts  which  are  covered  with  a 
growth  of  hair. 

Under  the  skull  there  is  a  firm,  tough,  rather  thick  mem- 
brane, which  acts  as  a  protection,  but  is  not  attached  to  the 
surface  of  the  brain.  When  this  membrane  is  cut  away  the 
brain  itself  appears,  displaying  a  soft,  grayish  mass,  looking 
as  if  it  were  composed  of  a  coiled-up  heap  of  soft  materials. 
This  peculiar  appearance  is  due  to  the  fact  that  the  outer  layer 
of  gray  matter  (about  as  thick  as  a  piece  of  silk  velvet)  is 
folded  or  tucked  in  a  complicated  manner.  The  folds  are 
called  convolutions. 

The  brain  is  divided  into  three  parts, — the  cer^ebrum,  or 
brain  proper;  the  cerebeVlum,  or  "little  brain '^;  and  the  cere'bral 
ganglia.     The  cerebrum,  in  man,  is  much  the  largest  part,  and 


THE  yEIiVOUS   SYSTEM. 


133 


is  the  only  part  seen  from  above. 
The  cerebral  ganglia  are  be- 
neath ;  the  cerebellum  is  behind 
and  beneath. 

The  whole  structure  is  very 
plainly  divided  into  a  right  and 
a  left  portion.  A  deep  groove 
or  parting  extends  from  the 
front  to  the  back  of  the  brain, 
forming  the  right  and  left  cere- 
bral hemispheres.  A  similar  ar- 
rangement exists  in  the  cerebel- 
lum. The  hemispheres,  both  of 
the  cerebrum  and  cerebellum, 
are  very  closely  united  by  their 
deeper  parts,  both  with  each 
other  and  the  cerebral  ganglia. 

The  brain  is  the  organ  of  the 
mind.  Strictly  speaking,  this 
statem.ent  refers  to  the  cortex 
of  the  cerebral  hemispheres,  the 
cortex  being  the  thin  outer  layer 
of  gray  matter.  The  cortex 
covers  all  the  convolutions,  and 
dips  down  into  the  infoldings 
of  them;  the  convolutions, 
therefore,  greatly  increase  the 
amount  of  the  gray  matter  of 
the  cortex.  We  can  estimate 
the  intelligence  of  an  animal 
from  his  brain,  by  observing 
how  numerous  the  convolutions 


Fig.  54,  —  Brain  and  spinal  cord.  C, 
cerebellum;  V,  fifth  pair  of  nerves 
(for  the  face) ;  MS,  lower  end  of  cord ; 
CVIII,  eighth  cervical  nerve ;  DXII, 
twelfth  dorsal  nerve ;  L  V,  fifth  lum- 
bar ner\'e.  The  nerves  are  seen  aris- 
ing from  the  spinal  cord. 


134  PHYSIOLOGY. 

are.  Stupid  animals  (as  the  rabbit)  have  few  or  none.  In 
men  of  great  intellect,  they  are  more  numerous  and  deeper 
than  in  men  of  weak  minds. 

The  size  of  the  cerebrum  proper,  as  compared  with  that  of 
the  cerebral  lobes  and  the  cerebellum,  affords  another  test  of 
mental  power.  In  man,  the  cerebrum  covers  the  cerebellum ; 
in  the  quadrupeds,  it  is  not  large  enough  to  do  so  ;  in  fishes,  it 
is  so  small  as  to  be  insignificant. 

In  speaking  of  the  size  or  weight  of  "  the  brain,"  we  com- 
monly include  all  three  parts ;  so  that  the  size  and  shape  of  a 
"  brain  "  is  the  same  as  that  of  the  whole  interior  of  the  skull 
containing  it.  In  this  sense,  a  fish's  brain  is  stated  to  weigh 
■5T0T  or  -g-oVo  of  l^is  body,  a  bird's,  2 w?  ^^^  ^  man's,  Jg.  The 
brain  of  man  is  not  only  proportionally  large ;  it  is  absolutely 
larger  than  that  of  any  animal  except  the  whale,  the  elephant, 
and  the  dolphin,  and  is  nearly  as  large  as  these.  One  of  the 
largest  brains  —  that  of  the  great  naturalist,  Cuvier  —  weighed 
1831  grammes. 

The  cells  of  the  brain  have  branches  (I'ig.  53).  From  these 
branches  nerve-fibres  pass,  which  serve  to  connect  the  cells. 
The  fibres  run  in  many  directions,  and  their  study  is  one  of 
the  most  complicated  parts  of  the  anatomy ;  but  we  know  that 
they  form  connections  between  the  right  and  left  halves  of  the 
brain  as  well  as  between  cells  of  the  same  side.  The  fibres 
also  pass  down  to  and  through  the  cerebellum  and  cerebral 
ganglia.  There  is  much  gray  matter  in  those  organs  ;  they  are 
not  believed  to  be  the  seat  of  mental  action,  but  to  be  connected 
with  the  senses  of  sight  and  hearing,  the  power  of  balancing, 
and  that  of  regulating  movements. 

It  is  impossible  to  prove  by  dissection  that  any  single  fibre 
starts  from  a  brain-cell  and  goes  down  through  the  ganglia 
into  the  spinal  cord.  Nevertheless,  it  appears  evident  that 
a  large  number  of  fibres  do  run  this  course.  They  pass  out 
from  the  skull  by  a  hole  in  its  base,  and,  united,  form  the 
spinal  cord,  which  lies  in  the  protected,  tube-shaped  cavity  of  the 
spinal  column,  extending  down  to  the  second  lumbar  vertebra. 


THE  NEltVOUS   l^Y^TEM. 


13; 


The  spinal  cord  (or  "  tlie  cord "")  has  many  cells,  besides  the 
fibres  already  mentioned ;  it  may  for  this  reason  be  regarded 
as  an  extension  of  the  base  of  the  brain  doAvnward.  We  may 
look  npon  the  brain  and  cord  as  one  organ,  the  whole  of  which 


Fig.  55.  —  Nerves  of  face  and  neck.  1,  facial  (motor  nerve) ;  10.  25,  27,  branches 
of  trifacial  (sensitive  nerves) ;  23,  occipital. 

is  of  nse  in  governing  motion,  while  only  the  upper  part  (cere- 
bral hemispheres)  is  connected  with  consciousness  or  with 
knowledge. 

Between  every  two  vertebrae  there  is  an  opening  on  the  right 


136  PHYSIOLOGY. 

side,  and  one  on  the  left,  out  of  which,  pass  a  pair  of  nerve- 
bundles,  one  on  each  side.  These  bundles  of  nerves  pass  to 
the  right  and  left  respectively,  in  the  direction  of  the  ribs,  and, 
dividing,  go  to  various  muscles  and  other  parts.  At  the  level 
of  the  arms  the  bundles  are  much  larger,  to  form  the  arm- 
nerves  5  at  the  small  of  the  back  they  are  still  larger,  in  order 
to  supply  the  great  nerves  of  the  legs.  These  are  termed  the 
spinal  nerves. 

There  are  also  nerves  coming  directly  from  the  base  of  the 
brain,  called  cerebral  nerves.  These  proceed  to  the  face,  neck, 
and  forehead ;  also  to  the  eye,  ear,  nose,  and  tongue,  to  provide 
for  the  special  senses. 

GANGLIONIC  OR  VISCERAL  SYSTEM   OF  NERVES. 

This  system  regulates  the  inner  parts  of  the  body  and  the 
blood-vessels,  parts  over  which  we  have  no  direct  control. 

A  "  ganglion  ^'  is  a  group  of  nerve-cells.  There  are  hundreds 
of  them  inside  of  the  body,  of  various  sizes  ;  they  are  connected 
with  each  other  and  with  the  cerebro-spinal  system  by  nerve- 
fibres,  and  they  send  nerves  to  all  the  viscera  or  internal  organs 
(of  which  the  stomach,  intestines,  liver,  kidneys,  heart,  lungs, 
and  brain  are  the  chief),  and  also  to  the  blood-vessels  and 
glands. 

The  name  "  sympathetic  nervous  system "  is  frequently 
applied  to  these  nerves  and  cells. 

PHYSIOLOGY  OF   THE  CEREBRO-SPINAL  SYSTEM. 

Each  nerve  has  the  duty  of  carrying  messages,  either  from 
the  brain  and  cord  or  to  it.  How  this  duty  is  performed  is  not 
fully  known;  their  action  reminds  us  of  the  action  of  tele- 
graph wires ;  but  it  seems  certain  that  the  agent  or  power  that 
carries  the  messages  is  not  electricity. 

Messages  are  carried  outward,  to  the  muscles  and  glands; 
they  are  brought  inward,  from  the  organs  of  sense  and  sensa- 
tion, and  carried  to  the  brain. 


THE  NF.nvoufi  srsTmi. 


137 


A  single  nerve-fibre  has  only  one  dnty  to  perform ;  it  trans- 
mits either  in  tlie  inward  or  the  ontward  direction,  but  not 
both  ways.  Yet  a  bundle  of  fibres  (such  as  is  commonly  kno^\ai 
as  a  nerve)  may  contain  nerves  of  both  sorts.  The  two  kinds 
seem  to  be  alike  in  structure. 


A.LINGUALia. 
V.  FACIALIS 
N.AURICULARISl 

V.  JUGUL  IMTERNA. 
CAROTIS  COMMUNIS 


Fig.  56. 


Nerves  of  face  and  neck.    The  parotid  gland  is  shown  in  front  of 
ear.    Arteries  {A),  veins  (F),  muscles  (3/),  nerves  (iV^). 


Sensation.  —  This  includes  the  special  senses  (sight,  hearing, 
smell,  taste),  the  sensations  of  touch,  and  heat,  and  general 
sensation. 

Special  senses  are  treated  elsewhere. 

The  sense  of  touch  belongs  to  the  skin  and  mouth.  It 
resides  in  certain  singular  small  bodies,  which  are  found  in 
the  skin,   and  are   connected  with   nerves.      They  are   most 


138 


PHYSIOLOGT, 


numerous  where  the  sense  is  most  acute,  as  on  the  finger-tips, 
the  palms  and  soles,  the  lips  and  face,  the  tongue  and  interior 
of  the  mouth.  This  sense  is  surprisingly  useful  to  persons 
who  are  deprived  of  sight.  By  practice  they  become  so  skilful 
as  to  read  the  letters  on  types  by  touching  them ;  they  also 
read  books  printed  in  raised  letters  for  their  especial  use,  by 
passing  their  fingers  over  the  letters.     (See  Tig.  51.) 

The  feeling  of  heat 
or  cold  needs  no  special 
explanation. 

General  sensation  is 
"that  which  is  experi- 
enced when  a  nerve  is 
laid  bare  and  touched." 
The  student  is  not 
likely  to  know  this 
from  experience .;  he 
may,  however,  under- 
stand that  it  is  a  sort 

FiG.57.— Nerve  of  smell  (olfactory  nerve)  at/  o  fpp-i-^™  ^^1.4^1.  rinpq 
is  on  the  floor  of  the  brain-cavity ;  the  fibres  ^^  leeimg  WUlCU  aoes 
descend  from  it,  through  the  bone,  spreading  j^ot  (like  touch  Or  the 
on  the  wall  of  the  nostril.  nix. 

sense  of  heat)  give  any 

particular  information,  but  is  only  a  feeling ;  and  that  when 

it  becomes  intense  it  is  pain. 

If  an  ordinary  nerve  in  a  limb  is  cut  across,  or  tied  tightly, 
or  even  pressed  upon,  it  can  no  longer  transmit  sensations. 
If  we  then  touch  a  part  of  the  skin  to  which  this  nerve  goes, 
the  touch  is  not  felt ;  the  part  seems  quite  dead.  This  is  often 
experienced  when  the  arm  or  leg  '^  goes  to  sleep." 

A  cut  nerve  may,  in  healing,  so  reunite  that  the  "  feeling  in 
the  parts  "  is  entirely  restored. 

Voluntary  Motion.  —  This  is  caused  by  the  contraction  of 
muscles,  acting  under  the  direction  of  an  order  sent  from  the 
brain,  by  means  of  nerve-fibres.  Some  fibres  pass  directly 
from  the  brain  to  the  face ;  others  first  pass  into  the  spinal 
cord,  then  go  from  the  cord  by  spinal  nerves. 


THE  NERVOUS   SYSTEM.  139 

Cutting,  tying,  or  pressing  a  nerve  of  a  limb  takes  away  the 
power  of  moving  the  muscles  to  which  that  nerve  goes.  This 
would  at  first  sight  apx^ear  to  show  that  one  and  the  same 
nerve  is  used  both  for  feeling  and  motion.  We  can,  however, 
prove  that  this  is  not  the  case.  The  nerves  can  be  traced  back 
to  the  spinal  nerves ;  these  can  be  traced  to  the  points  where 
they  leave  the  spinal  cord,  and  there  each  single  nerve  is  seen 
to  be  composed  of  two  bundles  of  nerves.  One  of  these 
bundles  (their  proper  name  is  spinal  nerve-roots)  is  composed  of 
nerves  of  sensation;  the  other,  of  nerves  of  motion,  as  has 
often  been  proved  by  experiment.  For  if  the  front  or  anterior 
root  be  cut,  in  a  living  animal,  the  effect  is  paralysis  or  loss  of 
power  of  motion ;  if  the  back  or  posterior  root  be  cut,  the 
power  of  sensation  is  lost. 

Paralysis  is  loss  of  power  of  motion.  It  is  sometimes  caused 
by  disease  in  the  brain,  as  in  apoplexy  and  tumors  of  the  brain. 
When  the  back  (i.e.  the  back-bone)  is  broken,  the  spinal  cord  is 
pressed  so  that  the  parts  below  the  injury  are  paralyzed.  If 
the  spine  is  broken  in  the  neck,  the  "neck  is  broken,"  and 
death  occurs  very  quickly. 

Reflex  Motion.  —  The  muscles  of  the  body,  which  regularly 
obey  our  wishes,  will  act,  in  certain  cases,  independently  of 
bhe  will.  If  a  sudden  motion  is  made  to  strike  a  person's 
face,  the  muscles  of  the  eyelids  act  suddenly  and  close  the  eyes  ; 
and  it  is  almost  impossible  to  prevent  their  doing  so,  even  if  we 
know  that  the  blow  is  a  friendly  one  and  not  intended  to  strike 
the  face.  Another  act  which  we  often  try  hard  to  prevent  is 
that  of  coughing  or  sneezing  when  dust  gets  into  the  throat 
or  nose.  It  would  seem  that  Nature  sometimes  takes  matters 
into  her  own  hands  and  makes  us  do  certain  things  before  we 
have  time  to  think  how  necessary  they  are. 

Many  actions  of  this  class  can  be  performed  without  the  help 
of  the  brain.  This  is  proved  by  the  experiment  of  removing 
the  cerebral  hemispheres  of  a  pigeon's  brain.  The  creature 
lives  and  can  be  made  to  eat,  but  he  is  extremely  stupid  and 
does  nothing  of  his  own  accord.     If  throAvn  into  the  air,  he 


140  PHYSIOLOGY. 

flies.  A  frog  treated  similarly  can  swim  and  jump  very  well, 
but  seems  to  do  nothing  of  himself.  In  such  cases,  it  is  be- 
lieved that  the  gray  matter  of  the  cerebral  ganglia  and  the 
spinal  cord  acts,  and  sends  messages  to  the  muscles.  The 
process  begins  when  the  animal's  skin  is  touched ;  then  sensa- 
tion is  carried  by  nerves  to  the  cord  and  ganglia;  then  the 
ganglia,  aroused,  send  back  an  order  to  the  muscles,  —  the 
animal  all  the  while  being  incapable  of  knowing  anything 
about  what  goes  on. 

What  is  the  nature  of  nervous  action?  We  cannot  be 
positive,  but  it  is  believed  that  a  certain  force  is  produced  in 
these  cells,  and  that  the  fibres  carry  the  force  to  the  muscles, 
to  order  them  to  work.  The  brain  contains  a  great  many  mil- 
lions of  the  cells,  many  of  which  are  connected  with  the  acts 
of  thinking,  remembering,  seeing,  hearing,  and  other  mental 
processes,  while  others  have  the  power  of  ordering  the  mus- 
cles to  move.  When  a  person  "uses  his  brain,"  the  cells  (or 
some  of  them)  become  more  active  than  usual.  When  we  move 
a  finger,  some  cells  in  the  brain  must  first  become  active,  and 
must  produce  an  order,  which  is  sent  down  along  some  nerve 
fibre  or  fibres  to  the  proper  muscle  of  the  finger. 

This  process  may  be  compared  to  a  man  firing  a  gun  by  pull- 
ing a  string.  The  man  represents  the  cells  in  the  brain ;  the 
string,  the  nerve-fibres  ;  the  lock,  the  arrangement  by  which 
the  nerve  is  connected  with  the  muscle ;  and  the  barrel  with 
its  charge,  finally,  represents  the  muscle  with  its  own  power 
of  action. 

Mental  Action.  —  The  faculties  of  the  mind  are  many,  and 
comprise  all  the  powers  of  sensation,  perception,  action, 
thought,  memory,  and  speech. 

All  powers  are  brought  into  action  by  the  aid  of  the  cells 
found  in  the  gray  matter  of  the  surface  of  the  cerebral  hemi- 
spheres. We  do  not  know  that  they  are  ever  exercised  without 
these  cells,  in  our  life  upon  earth. 

The  brain,  each  and  every  part  of  it,  is  dependent  on  a  good 
supply  of  fresh,  pure  blood  for  its  action.     The  same  is  true  of 


THE  NERVOUS   SYSTEM.  141 

every  other  organ  and  part  of  the  body ;  but  in  no  other  part 
does  such  a  striking  effect  occur  when  the  circulation  is 
stopped.  The  effect  is,  that  the  person  loses  consciousness, 
or  "  faints  " ;  all  the  actions  of  the  mind  cease  instantly,  and 
the  body  falls  like  a  corpse. 

In  sleep,  the  circulation  of  blood  in  the  brain  is  not  wholly 
cut  off,  but  only  lessened.  The  pulse  beats  more  slowly  and 
less  strongly.  In  a  very  deep  sleep  without  dreams  there  is 
least  blood  in  the  surface  of  the  brain;  in  light  sleep,  or  in 
dreaming,  there  is  more  blood,  but  less  than  when  awake. 

In  reading  the  list  of  the  mental  faculties  given  above,  the 
student  may  have  doubted  whether  it  was  right  to  include 
"  speech  and  actions  "  as  mental  faculties.  It  should  be  said, 
therefore,  that  there  is  the  strongest  proof  that  such  is  the  case. 

By  ''  speech  "  we  mean  the  power  of  intelligent  utterance  of 
thought,  such  as  no  beast  seems  to  possess.  Certain  birds  have 
the  power  of  uttering  words,  in  imitation  of  man,  but  it  is  very 
doubtful  whether  they  know  the  meaning  of  them.  We  say 
that  they  have  not  mind  enough  to  understand.  Children  are 
to  some  extent  like  these  birds :  they  can  learn  words  more 
easily  than  meanings.  There  is  a  remarkable  connection 
between  certain  parts  of  the  brain  and  the  faculty  of  speech, 
as  is  seen  in  the  fact  that  disease  affecting  the  surface  of  the 
brain  at  the  left  temple  regularly  produces  a  loss  of  power  to 
talk.  And  further :  the  brains  of  monkeys  (the  highest  in  devel- 
opment of  all  animals,  next  to  man),  though  exceedingly  like  the 
brains  of  man,  are  yet  distinctly  imperfect  in  that  very  region  (at 
the  left  temple)  where  man's  power  of  language  seems  to  reside. 

As  regards  "  action,"  it  is  true  that  certain  actions  seem  to 
require  very  little  or  no  attention  from  the  mind,  such  as  walk- 
ing or  riding.  But  there  are  other  muscular  acts  which  are 
highly  intellectual,  as  drawing,  painting,  sculpturing,  playing 
musical  instruments  ;  even  the  blows  of  the  blacksmith's  ham- 
mer and  the  strokes  of  the  woodman's  axe  have  to  be  given 
with  a  great  deal  more  judgment  than  people  suppose.  To 
crown  the  argument,  it  has  been  found  that  disease  or  injury 


142  PHYSIOLOGY. 

of  certain  parts  of  the  surface  of  the  brain  hemispheres  causes 
paralysis  of  the  muscles  of  certain  parts  of  the  body. 

HYGIENE. 

The  brain  is  affected  by  the  ill-health  of  many  other  parts 
of  the  body,  and  no  part  more  frequently  causes  such  disturb- 
ance than  the  stomach.  Over-eating  stupefies  the  mind ;  bad 
digestion  often  makes  the  mind  irritable  or  dull.  It  is  neces- 
sary that  persons  who  wish  to  do  good  brain-work  should 
have  good  and  regular  habits  of  eating.  Constipation  is  a 
very  disturbing  and  weakening  state,  particularly  in  its  effect 
in  dulling  the  mind  for  the  time.  Neglect  of  exercise  has  a 
similar  effect. 

Probably  no  one  thing  is  so  necessary  for  the  health  of  the 
brain  as  sleep,  —  sound,  natural  sleep,  neither  made  heavy  by 
drink  nor  made  light  and  dreamy  by  tea  or  coffee.  During 
sleep  the  brain  quietly  repairs  itself  after  its  waking  labors. 
We  do  not  know  very  well  what  takes  place,  but  we  do  know 
that  a  brain  which  was  tired  out  with  work  becomes,  after 
sound  sleep,  fresh,  strong,  and  ready  for  new  tasks.  The 
morning  ought  to  bring  a  feeling  of  new  life  and  power ;  if  it 
does  not,  —  if  we  wake  tired  and  discouraged,  —  there  is  some- 
thing wrong.  It  may  then  be  that  we  were  over-tired  on  the 
day  before  and  have  not  yet  got  rested,  or  we  have  been  up 
too  late,  or  have  eaten  unsuitable  things. 

Sleep  must  be  taken  regularly.  A  time  being  fixed  for  bed 
which  will  allow  for  plenty  of  sleep,  we  should  keep  to  the 
hour.  By  maintaining  a  habit  of  lying  down  and  closing  the 
eyes  at  the  same  time  every  evening,  we  soon  find  that  we  are 
fully  ready  for  sleep  at  that  time.  Once  in  bed,  waste  not  a 
moment,  but  drop  off  to  sleep  at  once. 

Different  persons  require  very  different  amounts  of  sleep. 
Young  infants  sleep  almost  all  the  time ;  children  of  four  or 
five,  nearly  half  the  time ;  those  of  ten  or  twelve,  ten  hours ; 
at  the  college  age,  most  students  require  eight  hours ;  many 


rilE  NERVOUS   IS  Y STEM.  143 

full-grown  men  sleep  less ;  and  in  old  age  many  sleep  much 
less.  Persons  may,  for  years,  take  less  sleep  than  they  need ; 
the  effect  is  a  gradual  weakening. 

In  order  to  have  sound,  healthy  sleep,  young  persons  should 
go  early  to  bed,  on  a  light  supper.  If  older  persons  sit  up  four 
or  five  hours  after  supper,  they  often  require  a  light  lunch 
before  bed. 

Bedrooms  must  be  aired  before  they  are  slept  in,  and  to  keep 
the  air  fresh  a  window  should  generally  be  left  partly  open, 
even  in  moderately  cold  weather.  Judgment  should,  however, 
be  exercised ;  there  is  nothing  gained  for  health  by  having  the 
water  freeze  in  the  pitcher  while  we  sleep.  A  room  kept  at 
the  day-temperature  of  Q>o°  or  70°  is  not  suitable  for  sleeping, 
except  in  the  case  of  infants  or  feeble  persons  :  it  makes 
a  person  delicate. 

Pure  air  by  day  is  also  very  necessary  for  the  health  of  the 
brain.  Scholars  can  work  better  in  a  well-ventilated  room, 
because  purer  blood  is  then  sent  to  the  brain ;  in  close,  crowded 
rooms  we  grow  sleepy,  because  the  impure  air  makes  impure 
blood,  which  does  not  give  the  brain  proper  support. 

The  best  time  for  hard  study  is  generally  the  forenoon; 
later  in  the  day  we  cannot  always  work  so  effectively.  Study 
must  not  occupy  the  hours  of  sleep ;  if  it  does,  we  generally 
"  have  to  pay  "  for  it  next  day.  Study  before  breakfast  agrees 
well  with  many ;  others  ought  not  to  study  or  exercise  before 
eating  something. 

EFFECTS  OF  ALCOHOLIC  DRINKS   UPON   THE  NERVOUS 
SYSTEM. 

There  is  no  part  of  the  body  upon  which  the  effects  of  alco- 
holic drink  fall  more  directly  than  upon  the  nervous  system. 
These  effects  are  such  that  they  can  be  seen  and  their  nature 
understood  with  ease.  The  alcoholic  beverages,  when  swal- 
lowed, are  absorbed  more  or  less  quickly  by  the  capillary  blood- 
vessels of  the  stomach.  They  pass  thence  to  the  liver,  then  to 
the  heart,  where  they  are  sent  out,  in  the  blood,  to  all  parts  of 


14  J:  PHYSIOLOGY. 

the  body.  In  short,  they  take  the  same  course  that  water  will 
when  drunk.  In  a  very  little  time  they  reach  the  brain,  where 
they  produce  some  effect  at  once. 

One  of  the  first  effects  is  that  of  increasing  the  amount  of 
blood  circulating  in  the  head.  This  will,  of  itself,  sometimes 
interfere  with  sleeping  when  sleep  is  wished  for ;  not  a  matter 
of  very  great  consequence  compared  with  the  other  effects. 

Besides  this,  alcohol  has  a  special  power  to  affect  the  brain ; 
which  power  may  in  some  cases  best  be  called  medicinal,  in 
other  cases  poisonous  or  narcotic. 

As  regards  the  mental  faculties,  it  has  often  been  supposed 
that  wine  and  similar  drinks  sharpen  the  powers  of  the 
mind,  awaking  or  spurring  it  up  and  giving  it  increased  quick- 
ness and  clearness.  Upon  this  point  we  ought  to  make  a  dis- 
tinction. Where  people  are  drinking  and  enjoying  themselves 
in  each  other's  society,  much  is  said  that  would  not  be  told  if 
all  present  were  quite  sober ;  much  is  said  that  seems  bright 
and  witty  to  those  present,  because  those  who  listen  are  them- 
selves a  little  "fou,"  as  the  Scotch  say  (i.e.  foolish),  but  which 
to  a  sober  outsider  seems  silly.  Whether  conversation  is  made 
brighter  and  wittier  by  this  "  convivial "  use  of  wine,  is  a  matter 
which  needs  no  great  amount  of  discussion  here.  Whatever 
the  effects,  they  mostly  pass  off  during  a  night's  sleep,  and 
the  men  awake  next  morning,  sometimes  with  more  or  less 
sickness  at  the  stomach,  and  headache,  sometimes  with 
nothing  apparently  unusual  about  them. 

Drowsiness  or  stupor  are  later  effects  of  alcoholic  drinks. 
For  a  person  who  has  been  drinking  heavily,  sleeping  is  there- 
fore a  natural  resort ;  and  if  he  has  nothing  else  to  do,  —  if 
no  business  or  duty  calls  upon  him  at  once,  —  sleep  is  the 
safest  thing  for  him.  But  it  is  quite  otherwise  if  he  goes 
directly  to  a  position  where  his  skill  and  tact,  his  quickness  of 
eye  and  steadiness  of  hand,  are  to  be  tried  to  their  utmost. 
The  man  whose  mind  is  spurred  by  alcohol,  making  him  the 
amusement  and  entertainment  of  a  gay  company,  is  not  the 
person  who   can  be  relied  on  to  drive  straight,   or   to  read 


THE  NEBVOUS   SYSTEM.  145 

the  danger  signal  on  the  track,  or  to  do  just  the  right  thing 
in  the  nick  of  time  to  save  the  ship.  Most  decidedly  the 
mind  loses  some  of  its  self-control,  becomes  less  quick  to  see 
and  hear  and  act,  and  is  less  to  be  relied  upon,  when  the  man 
is  a  little  under  the  influence  of  drink. 

One  symptom  of  this  slight  degree  of  intoxication  is  the  fact 
that  the  skin  becomes  less  sensitive  to  the  touch.  As  the 
degree  becomes  greater,  the  sense  of  touch  and  the  power  of 
feeling  pain  become  by  degrees  quite  lost,  and  a  man  drunk 
may  be  burnt  or  frozen  to  death  without  feeling. 

The  numbness  of  the  skin  is  not  due  to  the  action  of  alcohol 
in  the  skin,  but  to  the  numbing  or  dulling  effect  upon  the  brain 
itself. 

Alcohol  is  not  the  only  agent  which  produces  a  benumbing 
effect  upon  the  brain  and  nerves.  There  are  a  good  many 
medicines  which  act  more  or  less  similarly,  and  which,  in 
general,  are  potent  poisons,  though  often  of  the  highest  use- 
fulness in  the  hands  of  physicians.  Of  these  intoxicant 
medicines,  some  are  extracted  from  plants,  and  others  are 
manufactured  chemically. 

The  frequent  and  continuous  use  of  liquor  very  often  causes 
a  slight  but  steadily  increasing  decay  of  the  higher  qualities  of 
the  mind.  Not  only  does  the  intellect  suffer,  but  the  sense  of 
duty  becomes  less  active,  honor  and  ambition  grow  dull,  truth- 
fulness and  honesty  are  less  keenly  observed. 

The  condition  of  absolute  drunkenness  is  described  else- 
where. The  state  to  which  we  here  allude  is  that  of  slight 
or  incomplete  intoxication  repeated  day  by  day,  which  is  even 
more  injurious  to  the  entire  system  than  an  occasional  fit  of 
complete  drunkenness. 

There  is  a  strange  and  surprising  circumstance  observed  in 
some  men  while  intoxicated;  they  act  in  a  manner  totally 
unlike  their  sound  selves,  committing  crimes  which  are  not, 
we  should  say,  consistent  with  their  character,  and  afterwards 
seeming  to  be  totally  unaware  of  what  has  occurred.  This  is 
a  sort  of  temporary  insanity. 


146  PHYSIOLOGY. 

Considered  as  a  drug  witli  the  power  of  benumbing  tlie 
senses  and  stupefying  the  brain,  alcohol  belongs  to  the  class 
of  narcotics,  which  includes  ether,  chloroform,  opium,  hashish, 
belladonna,  chloral,  and  other  articles  in  common  use  in  medi- 
cine. As  this  book  does  not  undertake  to  teach  medicine,  it 
is  sufficient  to  say  of  these  drugs  that  each  has  its  peculiar- 
ities, that  each  can  cause  death  by  poisoning  if  taken  in  suffi- 
cient quantity,  and  that  thfe  medical  value  of  each  should  be 
decided  by  the  physician  using  them,  according  to  his  best 
judgment. 

There  are  people  who,  in  various  ways,  have  fallen  into 
the  wretched  habit  of  using  one  of  these  drugs,  and  "  cannot 
give  it  up."  They  will  say,  '^  It  is  like  tearing  soul  and  body 
apart  to  give  it  up.'^  One  of  the  worst  narcotics  and  the  hard- 
est to  abandon  is  opium;  an  opium-eater  consumes  it  daily, 
often  constantly  increasing  the  quantity  used,  and  finally  uses 
at  a  dose  enough  to  kill  a  dozen  men,  for  the  drug  loses  its  first 
power,  and  the  consumer  must  take  more  and  more. 

Tobacco  is  also  a  narcotic  ;  for  an  account  of  its  effects  the 
reader  may  refer  to  Cha^^ter  XII.  It  does  not  compare  with  the 
narcotics  named  above  in  its  injurious  effects. 


SYN^OPSIS. 

The  nervous  system  governs  thought,  sensation,  motion  (volun- 
tary acts,  circulation,  respiration,  digestive  movements),  and  secretion. 
Its  duty,  expressed  in  a  general  way,  resembles  that  of  the  commander 
and  officers  of  an  army;  the  other  organs  and  parts  of  the  body  being 
the  soldiers.     It  is  the  highest  part  of  our  system. 

The  nerve  elements  are  fibres  and  cells.  "A  nerve  "  resembles  a 
thread,  and  is  made  of  a  bundle  of  fibres  supported  by  a  strong 
sheath.  A  cell  is  a  small  mass  of  gray  matter  with  a  nucleus  and 
one  or  more  branches.     With  the  latter,  fibres  are  connected. 

The  cerebro-spinal  system  includes  the  brain,  spinal  cord,  and 
nerves  proceeding  from  them.  The  visceral  system  belongs  to  the 
viscera  and  the  circulation. 

The  brain  fills  the  entire  skull.  It  is  sheathed  hi  a  tough  mem- 
brane.     It   is   soft,    grayish,    and    convoluted.      It    consists   of    the 


THE  NEBVOUS   SYSTEM.  147 

cerebrum,  cerebellum,  and  cerebral  ganglia.  The  first  is  the  largest 
and  uppermost.  It  is  parted  into  the  right  and  left  hemispheres 
united  at  the  base. 

The  cortex,  a  thin  surface-layer  of  the  cerebrum,  is  the  organ  of  the 
mind.  Intelligence  is  proportional  to  its  development.  Numerous 
and  deep  convolutions  allow  a  large  development  of  cortex. 

The  size  of  the  cerebrum  proper  is  another  indication  of  mental 
power.  The  whole  contents  of  the  skull,  however,  are  commonly 
weighed  together.  Man's  brain  is  larger  than  that  of  any  other 
animal,  with  very  few  exceptions. 

The  cells  of  the  brain  are  jomed  to  each  other  by  many  fibres.  Other 
fibres  pass  to  the  cerebellum,  cerebral  ganglia,  and  spinal  cord. 

The  spinal  cord  contains  fibres  and  cells.  Both  it  and  the  brain 
govern  motion ;  but  the  cord  does  it  without  consciousness. 

The  spinal  nerves  are  large  bundles  passing  right  and  left  from  the 
cord  to  supply  the  body. 

The  ganglionic  system  is  composed  of  many  groups  of  cells,  called 
ganglia,  with  nerve-fibres.  It  is  connected  with  the  cerebro-spinal 
system  by  nerves.     It  supplies  the  viscera  and  circulation. 

The  nerves  carry  messages  outward,  from  the  brain  and  cord  to  the 
muscles  and  glands  ;  they  carry  messages  inward,  from  the  organs 
of  perception  and  sensation  to  the  cord  and  brain.  A  single  fibre 
does  not  transmit  in  both  directions.  A  bundle  of  fibres  (a  nerve) 
may  contain  fibres  acting  in  each  direction. 

The  sense  of  touch  belongs  to  the  skin  and  mouth.  Its  organs  are 
situated  in  the  papillae,  and  are  most  numerous  where  touch  is  most 
acute.     It  is  very  useful  to  the  blind. 

General  sensation  is  that  which  when  heightened  becomes  pain. 

A  cut  or  tied  nerve  cannot  transmit  messages  of  either  sort.  Pres- 
sure on  a  nerve  makes  a  limb  "  go  to  sleep."  Cut  nerves  may  in 
healing  recover  their  function. 

Voluntary  motion  obeys  orders  from  the  brain,  sent  through  the 
anterior  spinal  nerve-roots.  Sensation  passes  through  the  posterior 
roots.  This  is  proved  by  the  experiment  of  dividing  these  roots 
separately. 

Paralysis  may  be  caused  by  disease  or  injury  of  tlie  brain  or  cord, 
as  in  apoplexy,  tumors,  or  fractures. 

Reflex  action  occurs  independently  of  the  will.  It  causes  many 
useful  movements,  often  more  quickly  than  we  could  think  to  do 
them.    Some  such  actions  are  uncontrollable.    ]\Iany  can  be  performed 


148  PHYSIOLOGY. 

without  the  aid  of  the  brain  (experiments  with  animals).  The 
process  includes  sensation,  carried  to  the  spinal  cord  and  cerebral 
ganglia;  action  in  the  ganglia;  transmission  of  an  impulse  from 
ganglia  to  muscles. 

I^ervous  force  is  believed  to  be  generated  in  the  nerve-cells.  The 
process  of  voluntary  muscular  action  includes  a  series  of  acts,  com- 
pared to  firing  a  gun  with  a  string. 

Mental  action  depends  upon  the  cells  of  the  cortex  (surface)  of  the 
brain-hemispheres.  It  requires  a  supply  of  pure  blood  in  the  brain  ; 
stoppage  of  the  supply  causes  fainting.  In  sleep  the  circulation 
of  the  brain  is  lessened. 

Speech  and  voluntary  action  are  dependent  on  the  brain,  and  are 
properly  intellectual  functions. 

The  health  of  the  brain  is  much  dependent  on  that  of  the  stomach 
and  bowels.  Regular  habits,  exercise,  and  especially  sleep  are 
favorable. 

Sleep  should  be  sound  and  natural;  not  impaired  by  tea  or  coffee. 
It  must  be  regular.  Children  of  twelve  to  fourteen  years  require  ten 
hours ;  young  children  more ;  adults  less.  Sleep  repairs  the  brain. 
Waking  up  tired  shows  something  is  wrong  —  as  over-fatigue,  late 
hours,  unwholesome  food,  late  meals.  The  bedroom  must  be  cool 
and  airy. 

Pure  air  improves  the  action  of  the  mind.  The  forenoon  is  often 
the  best  time  for  study ;  before  breakfast  is  generally  a  bad  time. 

Alcohol  produces  some  of  its  first  and  most  important  effects  upon 
the  nervous  system.  It  reaches  the  brain  very  soon,  and  quickly 
increases  the  amount  of  blood  there.  It  has  also  a  medicinal  and  a 
poisonous  action  upon  the  brain.  The  mental  faculties  under  its 
influence  act  differently  from  their  usual  way ;  often  irregularly  and 
unsteadily.  A  benumbing  effect  is  common,  which  in  a  higher  degree 
becomes  drowsiness  or  stupor.  Sleep  is  a  common  result ;  dead- 
drunkenness  is  the  extreme.  Loss  of  sensibility  of  the  skin  is  a 
temporary  effect  of  this  state  of  the  brain. 

Continued  excess  in  the  use  of  alcoholic  drink  is  apt  to  impair 
both  mental  and  moral  faculties.  Frequent  daily  tippling  is  worse 
than  occasional  complete  drunkenness.  Alcohol  may  cause  temporary 
insanity,  in  which  the  moral  faculties  are  perverted. 

Narcotics  are  substances  which  stupefy.  Many  are  of  such  a 
nature  that,  when  a  person  acquires  a  habit  of  using  them,  it  is  almost 
impossible  to  break  off,  and  the  dose  has  to  be  increased  from  time 
to  time. 


THE  NERVOUS   SYSTEM.  149 


SUGdTESTED   QUESTIONS. 


Four  of  the  chief  functions  of  life  dependent  on  the  nervous 
system.  The  "  Seven  Senses."  Thought.  Motion.  Secretion.  How 
the  system  as  a  whole  is  governed. 

Anatomical  elements  of  the  nervous  system.  Their  magnitude. 
Fibres.  A  nerve.  Cells:  form,  structure,  chemical  components, 
nucleus,  branches.  A  mass  of  cells.  Ganglia.  Gray  matter.  Sheaths 
of  nerves.     Two  divisions  of  the  nervous  system. 

Cerebro-spinal  system  —  three  divisions.  Brain:  situation,  protec- 
tion, appearance  from  outside,  convolutions,  division  into  three  parts, 
division  right  and  left.  Cerebrum,  cerebellum,  cerebral  ganglia, 
hemispheres. 

Organ  of  the  mind.  Cortex:  its  form,  arrangement,  situation. 
Intelligence  estimated,  —  two  modes  of  testing.  Size  or  weight  of 
brain;  in  animals;  absolute,  relative.     Cuvier. 

Connection  between  cells ;  between  parts  of  the  brain.  Functions 
of  cerebellum  and  cerebral  ganglia. 

Spinal  cord :  connection  with  the  brain,  components,  general  func- 
tions, function  shared  with  the  brain,  function  not  possessed. 

Spinal  nerves  :  size,  situation. 

Cerebral  nerves. 

Ganglionic  (visceral)  system.     Ganglia.     Viscera. 

Duty  of  the  nerves.     Directions  in  which  messages  are  transmitted. 

Special  senses.  Touch,  where  perceived.  Organs  of  touch.  Deli- 
cacy of  touch. 

General  sensation.  Pain.  Cutting,  tying,  pressing  a  nerve.  A 
limb  "asleep."     Wounded  nerves. 

Voluntary  motion:  originates  where?  How  to  interrupt  the 
impulse  for  motion.  Spinal  nerve-roots,  their  functions.  Paralysis : 
causes. 

Reflex  motion,  instances.     Its  use.     Involuntary  acts.     Experiments 

on  animals. 

Natm-e  of  nervous  force  :  where  produced.  Cells  of  brain.  Acts 
of  will.     Firing  a  gun. 

Mental  action:  its  organ.  Pure  blood.  Loss  of  consciousness. 
Sleep.  Dreams.  Speech:  birds,  children,  words,  disease  of  brain, 
monkey's  brain.     Muscular  acts  :  connection  with  the  intellect. 

Disturbanceof  health  of  brain:  causes.     Sleep.     Awaking.     Causes 


150  PHYSIOLOGY. 

of  impaired  sleep.  Habits  of  sleep.  Amounts.  Last  meal  before 
sleep.  Bedrooms :  air,  temperature.  Ventilation  of  school-room. 
Time  for  hard  study. 

Alcoholic  drinks :  how  they  reach  the  brain.  Effects  upon  the 
brain  :  as  to  circulation,  sleep,  medicinal  effects,  activity  of  mind,  con- 
versation. Xext  morning.  Some  late  effects.  Sleep.  Steadiness 
and  accuracy.  Effects  on  the  skin,  and  cause.  Higher  faculties  of 
the  mind.  Daily  slight  intoxication.  Moral  insanity ;  and  criminality. 
Legal  views. 

Narcotics.     Habits.     Opium.     Tobacco. 

NOTES  FOR  TEACHERS. 

A  very  fair  idea  of  the  appearance  of  the  spinal  cord  can  be 
obtained  by  dissecting  small  fishes ;  the  process  is  easy,  and  the  brain 
and  cord  may  be  kept  together  in  alcohol.  The  brain  of  small  birds 
can  easily  be  removed  entire  with  scissors  and  knife.  If  a  mammal 
brain  is  desired,  that  of  the  sheep  will  serve  very  well,  and  costs  very 
little ;  but  the  removal  of  the  bones  of  the  skull  is  so  difficult  that  it 
may  be  advisable  to  let  the  butcher  saw  the  cranium  completely  across 
in  any  convenient  direction  before  attempting  to  extract  the  brain. 
Decomposition  begins  very  quickly  in  this  organ,  and  renders  it 
useless  for  our  purpose  ;  the  pieces  should  be  well  hardened  in  alcohol, 
and  are  then  ready  for  use  at  any  time.  Fresh  specimens,  of  course, 
have  a  value  and  beauty  of  their  own. 

The  expression  "  special  senses  "  is  employed  in  this  chapter  in  its 
usual  way.  Strictly,  however,  the  sense  of  touch,  and  that  of  heat  or 
cold,  are  also  special,  as  opposed  to  the  general  sensation  already 
described. 


CHAPTER.  IX. 


THE  EYE. 


The  eye  is  a  globe  or  ball,  lying  in  a  deep  cavity  of  the 
skull,  called  the  socket.  Its  sides  and  back  are  protected  by 
the  skull;  its  front  is  covered, by  the  eyelids.  What  we  see 
is  only  a  small  part  of  the  globe.    (See  Tig.  58.) 

The  eyeball  does  not  come  into  close  contact  with  the  bones 
of  the  socket,  but  rests  upon  a  cushion  of  soft,  yielding,  fatty 


Fig.  58.  —  The  eyeball  in  its  socket,  with  the  muscles  that  move  it.  At  the 
right  is  seen  the  projecting  nasal  bone,  with  part  of  the  cheek-bone;  the  eye 
rests  on  the  latter.  Through  the  transparent  cornea,  the  pupil  is  faintly  see'n. 
2,  external  rectus  muscle,  cut  and  turned  down  to  expose  the  back  of  the 
eye;  3,  internal  rectus;  4,  inferior  rectus;  5,  superior  rectus;  0,  superior 
oblique,  running  through  the  pulley,  7;  8,  inferior  oblique;  9,  elevator  of  the 
upper  lid.  The  optic  nerve  projects  from  the  back  of  the  eye  as  a  cord  of 
considerable  size;  a  portion  has  been  cut  a.way. 

151 


152 


PHYSIOLOGY. 


tissue^  whicli  "gives"  when  the  eye  receives  a  blow.  If  it 
were  not  for  this  arrangement;  the  eye  might  easily  be  rup- 
tured by  being  struck. 

The  front  of  the  eye  is  a  smooth  surface,  over  which  the 
lid  fits.  A  little  moisture  is  found  between  the  lids  and  the 
globe,  which  enables  the  lids  to  move  smoothly  and  quickly 

over  the  surface.  In  shut- 
ting (winking),  the  lids  carry 
some  moisture  over  the  front 
of  the  eye  and  preserve  it 
from  drying ;  they  also  sweep 
small  particles  of  dust  off. 
The  moisture  is  chiefly  fur- 
nished by  the  mucous  mem- 
brane which  covers  the  front 
of  the  eye  and  the  inside  of 
the  lids.  On  the  edge  of  each 
lid,  near  the  nose,  may  be  seen 
a  point  or  dot,  which  is  the 
opening  of  a  small  tube  which 
carries  off  the  moisture  that 
is  not  needed  to  the  nostril. 

The  eyelashes  are  so  placed 
as  to  catch  dust  which  might 
otherwise  fall  into  the  eye  from  above. 

The  eyeball  has  several  coats.  The  outer  one  {sderot'ic)  is 
white  and  tough ;  but  at  the  forepart  of  the  globe  a  circular 
portion  of  the  sclerotic  becomes  transparent.  This  portion  is 
called  the  cor^nea. 

The  "  white  of  the  eye  "  is  that  part  of  the  sclerotic  which 
we  can  see.  Behind  the  cornea,  and  in  full  view,  is  a  circular 
object,  the  iris^  colored  blue,  gray,  green,  brown,  or  nearly 
black.  The  iris  is  a  flat,  round  curtain,  attached  by  its  edge, 
just  behind  the  edge  of  the  cornea.  Its  use  is  to  regulate  the 
amount  of  light  that  enters  the  eye.  At  its  centre  is  a  small 
round  hole,  the  pupil,  through  which  all  the  light  enters  the 


Fig.  59.  —  Front  of  the  left  eyelids,  with 
the  lachrymal  canals  and  nasal  ducts 
exposed  by  dissection.  1,  1,  lachry- 
mal canals ;  2,  lachrymal  sac ;  3,  lower 
part  of  nasal  duct;  5,  fleshy  projec- 
tion at  inner  corner  of  eye ;  between 
4  and  5  are  two  points,  showing  the 
openings  of  the  lachrymal  canals. 


THE  EYE.  153 

eye ;  this  hole  grows  larger  in  a  dim  light  and  smaller  in  a 
bright  light.  This  can  be  seen  by  holding  a  hand-glass  and 
facing  a  window ;  if  one  hand  is  held  so  as  to  screen  both  eyes, 
and  then  quickly  removed,  the  i^npil  will  be  seen  contracting. 
The  contraction  is  caused  by  a  little  ring  of  muscle  sur- 
rounding the  pupil,  which   acts  like   the  orbicularis   of   the 


Ciliary  Body. 


Internal 

Rectus 

Muscle 


Retina. 
Choroid  coat. 


Sclerotic  coat        \  i  \\\j 

Nerve  sheath         Optic  nerve 
Fig.  60.  —  Horizoutal  section  through  left  eyeball. 

mouth.  Opening,  or  dilatation,  is  caused  by  the  action  of 
small  fibres  which  run  from  the  pupil  toward  the  circiunfer- 
ence  of  the  iris. 

In  front  of  the  iris  and  behind  the  cornea  is  a  space  filled 
with  a  fluid  nearly  the  same  as  water,  —  the  a^queous  hu^mor. 


154  PHYSIOLOGY. 

Beliind  the  iris  is  a  lens,  the  crys'taUijie  lens;  and  behind 
that  is  the  main  cavity  of  the  eye,  surrounded  by  the  walls  of 
the  globe,  and  filled  with  a  transparent  material  consisting 
chiefly  of  water,  —  the  vit'reous  humor. 

The  eye  may  be  compared  with  a  little  camera  obscura,  such 
as  is  used  in  photographing  :  the  chief  differences  are  that 
the  interior  of  the  eye-camera  is  filled  with  watery  material 
instead  of  air,  and  is  rounded,  and  not  flat.  The  lens  causes 
the  rays  of  light  which  come  through  the  pupil  to  make  a 
picture  of  what  is  in  front  of  the  eye.  In  a  photographic 
camera  the  real  picture  is  seen ;  in  the  eye  it  could  be  seen 
(if  a  convenient  opening  could  be  made  in  the  eyeball)  upon 
the  back  and  sides  of  the  cavity,  like  a  painting  on  the  inside 
of  a  teacup. 

The  inner  surface  of  the  eye,  where  the  picture  is  formed, 
consists  of  a  thin  black  membrane,  over  which  lies  a  still 
thinner  layer  of  nerves  and  nerve-endings,  called  the  retHna. 
The  picture  is  on  the  retina.  The  retina  perceives  the  colors 
and  forms.  Its  nerves  carry  their  impressions  (as  telegraph 
wires  carry  their  messages)  to  a  central  point  at  the  back  of 
the  retina,  where  the  whole  impression  is  taken  by  the  optic 
nerve  and  carried  to  the  brain. 

Kays  of  light,  before  coming  to  the  retina,  must  pass  through : 
1,  the  cornea ;  2,  the  aqueous  humor ;  3,  the  lens ;  4,  the 
vitreous  humor. 

The  lens  is  shaped  like  a  burning-glass ;  it  brings  light  to 
a  focus  as  a  burning-glass  does.  If  the  burning-glass  is  held 
too  near  the  paper,  or  too  far  away,  the  spot  of  light  is  blurred. 
So  in  the  human  eye ;  if  the  retina  should  happen  to  be  too 
far  back  from  the  lens,  or  too  near  it,  the  picture  would  be 
blurred.  This,  indeed,  often  happens.  Near-sighted  eyes  are 
usually  longer,  when  measured  from  front  to  rear,  than  they 
should  be,  while  far-sighted  eyes  have  the  opposite  defect. 
Wearing  glasses  corrects  the  difficulty  and  gives  a  clear  pic- 
ture.    ISTear-sight    exists  when  a  person  cannot  see  at  a  dis- 


THE  EYE. 


165 


tance  as  well  as  tlie  average,  but  does  see  well  near  at  hand: 
far-sight  is  the  opposite  state. 

We  have  the  power  of  changing  the  shape  of  the  lens  (making 
it  more  curved),  by  a  little  effort,  with  a  certain  small  muscle, 


Fig.  61 .— Refraction  of  light  in  the  eye.  Diagram  1,  normal  eye,  bringing 
parallel  rays  exactly  to  a  focus  on  the  retina ;  2,  the  same,  adapted  to  near 
rays,  the  dotted  lines  showing  the  change  made  from  1,  making  the  lens 
thicker;  3,  far-sighted  eye,  focussing  ravs  behind  the  retina;  and  4,  near- 
sighted eye,  focussing  rays  in  front  of  the  retina. 

situated  inside  of  the  eyeball.     (See  Fig.  60.)     This  act,  called 
accommodation,  has  to  be  performed  when  we  are  looking  at 


156  PHYSIOLOGY. 

objects  that  are  nearer  than  usual.  If  the  object  is  held  very- 
near,  we  have  a  feeling  of  "  straining  to  see  it " :  this  straining 
is  bad  for  the  eye  and  tends  to  make  persons  near-sighted. 

As  people  grow  older  they  partly  lose  this  power  of  accom- 
modation. A  child  can  see  objects  plainly  at  a  distance  of 
three  inches  without  much  effort ;  at  fifteen  years  he  cannot 
see  so  near ;  and  the  change  gradually  goes  on^  until^  at  about 
forty,  many  persons  are  obliged  to  hold  the  book  two  or  three 
feet  away  in  reading.  This  is  called  growing  old-siglited,  and 
requires  glasses  of  the  convex  sort. 

Muscles  of  the  Eyeball. — Besides  the  muscles  of  the  iris 
and  of  the  lens,  which  are  internal,  there  are  several  external 
ones,  which  move  the  eye  in  various  directions,  pointing  it  to 
objects  we  wish  to  see.  Each  eyeball  has  a  straight  muscle 
above,  one  below,  and  one  at  each  side,  besides  two  which  are 
inserted  obliquely  and  give  a  twisting  motion.  The  muscles 
are  fastened  by  one  end  to  the  eyeball,  by  the  other  to  the 
socket.  In  moving  the  eye  we  use  them  unconsciously,  though 
not  involuntarily.  If  a  muscle  on  one  side  of  the  eye  is  weak, 
the  one  on  the  opposite  side  overbalances  or  overpowers  it, 
and  gives  the  eye  a  turn  or  twist  away  from  the  straight  line. 
This  is  one  cause  of  squinting.      (See  Fig.  58.) 

NEAR-SIGHT. 

Among  savage  nations,  where  no  books  are  used,  almost 
every  one  has  good  sight,  and  near-sight  is  hardly  known. 
The  use  of  books  and  writing  is  a  great  blessing  to  man,  but 
has  certainly  done  harm  to  many  individuals  by  weakening 
their  vision.  The  greatest  amount  of  near-sight  is  found  among 
the  Germans,  who  are  the  greatest  students,  and  whose  chil- 
dren study  considerably  more  than  ours  do. 

Many  inherit  near-sight  from  their  parents.  In  others  it 
begins  while  they  are  at  school.  In  all,  it  is  extremely  likely 
to  go  on  increasing  unless  great  precautions  are  taken.  Chil- 
dren at  study,  or  while  writing,  seem  to  have  a  natural  wish 


THE  EYE.  157 

to  get  their  eyes  close  to  the  book,  —  the  very  worst  thing  for 
near-sight. 

Near-sighted  eyes  may  be  healthy  in  other  respects,  but 
(in  not  a  few)  there  is  a  tendency  to  grow  worse  rapidly,  until 
finally  the  sight  is  nearly  lost,  and  spectacles  are  of  very  little 
more  use:  almost  complete  blindness  may  be  the  result  of 
this  state. 

A  child  that  is  at  all  near-sighted  ought  to  be  most  careful 
to  observe  these  rules.  In  particular,  he  should  have  a  good 
light;  keep  the  book  as  far  away  from  the  eyes  as  convenient; 
sit  up,  and  not  stoop  over  the  work ;  do  no  study  of  fine  maps 
or  close  small  print;  and  execute  no  fine  work  with  pen  or 
needle. 

FAR-SIGHT. 

Far-sight  (technically  called  over-sight,  or  hyperopia)  is  not 
an  uncommon  affection  of  the  eye  in  childhood ;  but  it  is  only 
within  recent  years  that  much  attention  has  been  paid  to  it. 
Those  suffering  from  it  cannot  fix  the  eyes  on  near  objects,  as 
in  reading,  with  the  same  ease  that  others  can.  The  effort  to 
read  produces  pain  in  the  eye  or  head,  and  sometimes  other 
troubles,  which  may  become  so  serious  a  matter  as  to  force  the 
child  to  give  up  school.  It  is  most  important,  therefore,  to 
know  that  these  children  possess  eyes  shaped  like  the  eyes  of 
old  persons,  and  that  their  trouble  can  be  relieved  by  wearing 
"  old-sighted  "  glasses. 

To  avoid  dangerous  mistakes,  medical  advice  should  be  taken 
before  choosing  glasses  for  near-sight,  far-sight,  or  any  other 
defect  of  vision. 

HYGIENE. 

There  are  very  few  professions  or  trades  which  do  not  re- 
quire good  eyesight,  though  there  are  great  differences.  Well- 
educated  people,  in  particular,  require  to  make  great  use  of  their 
eyes  in  their  work.  Children  should  begin  when  young  to  obey 
the  rules  which  will  save  them  from  hurting  their  eyesight. 

The  eyes  are  "tried''  or  tired  in  various  ways.     The  rules 


158  PHYSIOLOGY, 

which  are  here  given  are  intended  to  apply  to  reading,  writ- 
ing, drawing,  and  other  school  work,  besides  sewing  and  em- 
broidering. To  save  repetition,  the  word  "  read  "  is  used  in 
the  rules  to  signify  any  or  all  of  these  operations. 

RULES    FOR    PRESERVING    GOOD    SIGHT. 

1.  Do  not  read  at  or  after  sunset  by  natural  light. 

2.  Reading  out  of  doors  is  commonly  trying  to  the  eyes;  there  is 
too  much  light. 

3.  Do  not  read  with  sunUght  faUing  on  the  book. 

4.  Do  not  read  with  a  window,  or  a  light,  directly  in  front  of  you, 
unless  you  have  a  screen  to  protect  the  eyes. 

5.  Protect  the  eyes  with  blue  or  gray  glasses  when  the  sunlight  on 
the  snow  is  dazzling ;  many  require  them  at  the  seashore  also. 

6.  ISTever  read  by  a  flickering  light. 

7.  Use  a  screen  to  keep  off  the  heat  of  the  burner  if  near  your 
head.     The  head  must  not  be  hot  while  reading. 

8.  Use  light-colored  paper  and  strong  black  ink  or  pencil  for  writing. 

9.  Prefer  daylight  for  reading.  It  is  well  for  students  to  save  an 
hour  of  daylight  at  the  beginning  of  the  day  by  having  an  early 
breakfast. 

10.  Reading  before  breakfast,  especially  by  artificial  light,  is  bad 
for  the  eyes  of  most  persons.  The  body  is  weakest  at  that  time,  and 
the  eyes  are  weak  when  the  body  is  so. 

11.  Do  little  eye  work  when  tired  or  sleepy. 

12.  Stop  and  rest  when  the  eyes  feel  tired  or  sore.  Rest  often,  in 
any  case. 

13.  Do  not  undertake  close,  hard  study  soon  after  dinner. 

14.  Have  the  clothing  loose,  especially  at  the  neck,  and  sit  erect 
while  reading,     l^ever  read  lying  down. 

15.  From  fourteen  to  eighteen  inches  is  a  good  distance  for  the 
book  or  paper. 

16.  After  some  fevers  (measles,  scarlatina,  diphtheria)  the  eyes  may 
be  weak  for  a  long  time,  and  in  that  case  the  scholar  must  be  almost 
wholly  kept  from  using  his  eyes. 

If  a  small  object  gets  into  the  eye,  it  should  first  be  looked 
for  on  the  front  of  the  eyeball,  and  when  found,  gently  wiped 


THE  EYE.  159 

off  with  tlie  corner  of  a  handkercliief.  If  not  seen  there,  the 
upper  lid  may  be  rolled  over  and  the  object  sought  on  the 
reversed  inside.  This  operation  is  performed  with  a  lead-pen- 
cil, laid  flat  on  the  upper  part  of  the  lid ;  the  lashes  are  taken 
hold  of,  and  the  lid  pulled  back  over  the  pencil.  If  necessary, 
search  the  lower  lid  in  like  manner. 

The  wind,  blowing  long  and  violently  upon  the  eye,  may 
cause  painful  inflammation  of  the  front  part.  Dust,  sand,  and 
excessive  sunlight  may  do  the  same. 

As  too  much  sound  can  make  the  ear  deaf,  so  too  much  light 
can  make  the  eye  blind.  This  may  take  place  instantaneously 
when  looking  at  the  sun. 

Blindness,  complete  or  partial,  can  be  caused  by  anything 
which  obstructs  the  passage  of  light,  or  which  injures  the 
retina  or  nerve  or  brain.  The  following  are  some  of  the  chief 
causes  :  — 

1.  The  cornea  may  lose  its  transparency,  or  may  become  per- 
forated, in  inflammation.  There  is  a  disease  called  pu'rulent 
ophthal'mia,  which  attacks  the  front  part  of  the  eye  and  pro- 
duces blindness.  It  is  very  easily  caught  by  one  child  from 
another ;  it  may  be  taken,  for  instance,  by  a  healthy  child,  in 
wiping  its  face  on  a  towel  used  by  a  diseased  child.  It  is 
common  among  children  who  live  together,  great  numbers 
sleeping  crowded  in  one  room,  and  w^ho  have  poor  food  and 
poor  air.     Diphtheria  or  small-pox  may  cause  this  blindness. 

2.  Weakly,  dirty,  scrofulous,  ill-fed  children  often  have  sore 
eyes,  with  red  lids  and  a  blurring  of  the  front  of  the  cornea. 
Great  cleanliness  is  required  in  the  care  of  such  eyes. 

3.  Any  wound  or  disease  that  injures  the  optic  nerve  may 
cut  off  the  sight ;  the  eye  may  form  a  clear  image,  but  the 
image  will  not  be  carried  to  the  brain,  and  so  the  mind  will 
not  know  of  it. 

4.  The  lens  grows  opaque  in  the  disease  called  cataract, 
which  is  very  rare  in  childhood. 


160  PHYSIOLOGY. 


SYNOPSIS. 

The  eye  or  eyeball  is  protected  by  the  socket  and  the  lids ;  it  rests 
on  a  cushion  of  soft  tissue.  The  mucous  membrane  of  the  front  of 
the  eye  secretes  moisture,  which  facilitates  the  movements  of  the  lids ; 
superfluous  moisture  is  carried  off  into  the  nostril.  The  eyelashes 
catch  dust. 

The  outer  coat  of  the  eye,  the  sclerotica,  is  tough.  A  part  of  the 
front  is  transparent,  and  is  called  the  cornea.  The  white  belongs  to 
the  sclerotica.  The  iris,  or  colored  part,  is  a  curtain  behind  the  cornea, 
with  an  aperture,  the  pupil,  varying  in  different  lights ;  the  change  is 
due  to  the  muscles  composmg  the  iris. 

The  aqueous  humor  is  in  front  of  the  iris,  the  crystalline  lens  just 
behind  the  iris,  and  the  vitreous  humor  fills  the  main  part  of  the  eye- 
ball. 

The  eye  is  a  camera,  with  spherical  interior.  The  rays  of  light  form 
a  picture  on  the  retina,  or  layer  of  nervous  substance,  at  the  back  of 
the  eye.  The  retina  receives  an  impression  of  light ;  the  optic  nerve 
carries  it  to  the  brain,  where  the  impression  is  perceived. 

The  lens  concentrates  light  like  a  burning-glass.  It  requires  to  be 
placed  at  a  certain  "  focal  distance  "  from  the  retina.  An  eyeball  that 
is  too  long  (in  near  sight)  or  too  short  (in  far  sight)  from  front  to 
rear  disturbs  this  relation  and  gives  a  blurred  image.  We  have  some 
power  to  change  the  shape  of  the  lens ;  this  act  may  cause  a  sense  of 
straining  the  eye;  this  power  is  lost  by  degrees  as  life  advances. 

The  eye  is  moved  in  various  directions  by  several  small  muscles. 
Affections  of  these  muscles  may  cause  squinting. 

Near-sight  is  peculiar  to  civilized  nations,  especially  those  where  a 
great  deal  of  studying  is  done.  It  is  often  inherited.  It  may  begin 
at  school.  It  is  very  likely  to  increase.  In  some  cases  it  causes  nearly 
total  loss  of  sight.  Strain  of  the  eyes  in  fine  work,  with  poor  light, 
and  holding  the  eyes  close,  are  causes. 

Far-sight  in  children  makes  it  diflBcult  to  apply  the  eyes  to  school 
work  without  suffering.     It  requires  the  use  of  glasses. 

(The  "  rules  "  need  not  be  repeated.) 

Small  objects  can  be  taken  out  of  the  eye  with  a  little  skill.  Inflam- 
mation may  be  caused  by  wind,  dust,  excessive  light. 

Blindness  may  be  caused  by  purulent  ophthalmia,  a  disease  of 
neglected  children,  in  crowded  rooms,  with  poor  food;  also  by  small- 


rriE  EYE.  101 

pox  or  diphtheria.  Scrofulous  and  ill-kept  children  often  have  chronic 
sore  eyes,  with  weakened  sight.  Disease  of  the  optic  nerve,  or  of  the 
lens,  may  cause  blindness. 


SUGGESTED   QUESTIONS. 

Socket  of  eye.  Protection  of  the  eyeball.  Blows.  Eyelids  :  motion  ; 
moistui-e.     Eyelashes. 

Coats  of  eye.  Sclerotic.  Cornea.  White.  Iris.  Pupil;  movements. 
Aqueous  humor.  Lens.  Vitreous  humor.  Camera;  shape.  Retina. 
Focussing".  Transference  of  visual  impression.  The  path  of  a  ray  of 
light.  Defects  in  focussing.  Deviations  from  normal  form  of  lens. 
Near-sight;  far-sight.  Accommodation.  Straining  to  see  near  ob- 
jects.    Change  with  advance  in  years.     Old-sight. 

External  muscles.     Squinting. 

Near-sight :  where  prevalent ;  causes.  Tendency  of  near-sight ;  re- 
sults in  extreme  cases.     Cautions  for  those  near-sighted. 

Far-sight :  in  childhood ;  symptoms ;  consequences  ;  means  of  relief. 

(Rules.) 

Way  to  remove  objects  from  the  eye.  Causes  of  inflammation. 
Light  striking  the  eye.  Causes  of  blindness.  Purulent  ophthalmia: 
symptoms  ;  causes.  Other  diseases  causing  blindness.  Chronic  sore 
eyes.     Injury  of  optic  nerve.     Cataract. 


NOTES   FOR   TEACHERS. 

The  eye  of  most  quadrupeds  is  rather  too  well  protected  by  the  skull 
to  be  easily  studied  in  situ.  The  butcher  can  readily  furnish  a  supply, 
taken  fresh  from  large  animals.  The  lens  can  easily  be  removed,  and 
made  to  magnify  print.  The  toughness  of  the  outer  coat  and  the 
abundant  black  pigment  of  the  interior  of  the  eye  will  be  noticed. 

Freezing  an  animal's  eye  (with  a  mixture  of  ice  and  salt)  enables 
us  to  cut  it  in  two,  giving  instructive  views  of  the  interior.  A  fish's 
eye,  with  its  nearly  globular  lens,  may  be  compared  with  the  above. 


CHAPTER   X. 
THE   EAE. 

DESCRIPTION. 

That  which,  we  commonly  call  the  ear,  the  part  which  is 
seen,  is  scientifically  called  the  concha,  from  its  resemblance 
to  a  sea-shell  (Latin,  concha). 

The  passage,  an  inch  and  a  quarter  in  length,  leading  to  the 
drum,  is  called  the  mea'tus}  It  is  directed  forward,  and  the 
drum  can  seldom  be  seen  without  the  aid  of  an  instrument. 
It  is  lined  with  skin ;  at  its  outer  part  it  has  little  glands, 
which  secrete  the  ear-wax  or  ceru'men. 

The  end  of  the  meatus  is  closed  by  a  sort  of  skin  or  mem- 
brane, tightly  stretched  across  like  the  head  of  a  drum.  It  is 
commonly  called  the  drum  of  the  ear,  though  drum-head  would 
be  a  better  term.^  Behind  this  is  a  small  cavity  (which 
corresponds  to  where  the  drum  should  be),  called  the  tym- 
pan'ic  cavity,  or  middle  ear. 

In  the  middle  ear  there  is  a  set  of  small  bones  of  peculiar 
shape,  resembling  a  hammer,  an  anvil,  and  a  stirrup.  They 
are  joined  together  in  a  string,  which  reaches  across  the 
cavity  of  the  middle  ear,  the  hammer  at  one  side  touching  the 
drum,  and  the  stirrup  at  the  other  resting  on  an  opening  in 
the  side  of  the  cavity  which  leads  to  another  region,  called  the 
inner  ear  or  labyrinth.  This  cavity  is  composed  of  a  curious 
set  of  winding  channels,  tunnelled  out  of  the  middle  of  the 

1  Latin,  meatus  auditorins  extermis,  outer  auditory  passage. 

2  Memhra'na  tym'pani  (drum-head)  is  its  scientific  nam?. 
162 


THE  EAR.  163 

imrd  bone  of  tlic  skull.  One  of  the  channels  is  spiral,  like 
a  snail-sliell ;  tlie  others  are  shaped  like  loops.  These  curious 
passages  are  occupied  by  the  si)reading,  fringe-like  termina- 
tions of  the  nerve  of  hearing. 


Fig.  62.  — ■  The  ear,  cut  across  vertically.  A,  meatus,  outer  part ;  B,  inner  part ; 
C,  drum,  divided  near  the  middle;  D,  middle  ear;  E,  Eustachian  tube.  The 
labyrinth  is  above  the  letter  D.    The  small  bones  are  not  represented. 

rrom  the  middle  ear  there  is  a  passage,  called  the  Eusta- 
chian tube,  which  leads  forward  and  downward  and  ends  in 
the  upper  part  of  the  throat.      (See  Tig.  52,  number  10.) 

Each  ear  is  entirely  independent  of  the  other. 

FUNCTIONS. 

The  ear  is,  of  course,  the  organ  of  hearing.  The  sound 
comes  through  the  air  in  waves,  which  are  not  seen,  but  only 
heard.  Such  waves  are  more  like  a  thrill  or  a  trembling  than 
the  waves  we  see  in  water.  By  placing  the  hand  on  almost 
any  musical  instrument  while  it  is  played  upon,  esj)ecially  if 


164  PHYSIOLOGY. 

it  has  a  deep  strong  tone,  we  can  feel  the  thrill  of  the  sound- 
Avaves.  By  listening  at  one  end  of  a  log  while  another  person 
whispers  at  the  other,  we  can  observe  how  sound  is  conveyed 
by  a  piece  of  solid  wood. 

The  part  which  hears  is  the  inner  ear,  where  the  nerves  are. 
All  the  other  parts  serve  to  catch  the  vibrations  and  convey 
them  to  that  part.  The  concha  or  external  ear  is  not  of  very 
great  importance,  but  it  is  of  some  use  in  collecting  the  sound- 
waves and  throwing  them  towards  the  meatus,  as  an  ear-trum- 
pet does.  The  drum  catches  the  sounds,  and  vibrates  in 
the  most  delicate  way  at  every  wave.  The  small  bones  pass 
the  vibrations  of  the  drum  on  to  the  labyrinth,  where  they 
strike  against  the  fine  fringes  of  nerve.  Here  the  sound  for 
the  first  time  comes  in  contact  with  nerve,  and  stimulates  it. 
This  stimulation  is  carried  by  a  cord  of  nerve-fibres  (auditory 
nerve)  to  the  brain ;  whereupon,  we  become  conscious  of  sound. 

HYGIENE. 

Dirt  and  dust  seldom  penetrate  to  the  farther  end  of  the 
meatus;  they  are  mostly  caught  on  the  sticky  sides  of  the 
passage  near  the  outlet.  A  very  little  wiping  out  will  suffice 
for  neatness.  A  daily  washing  of  the  outer  parts  (the  concha) 
on  all  sides,  with  good  soap  and  water,  is  wholesome ;  but  when 
we  reach  the  passage,  we  ought  to  go  in  no  deeper  than  we 
can  most  easily  reach  with  the  tip  of  the  little  finger  covered 
with  a  damp  cloth.  Ear-picks  are  dangerous,  as  they  may  reach 
the  drum  and  injure  it,  thus  causing  deafness. 

The  wax  usually  tends  to  move  outward,  and  can  be  removed 
when  it  comes  in  sight.  In  some  persons  it  collects  in  a  lump 
near  the  drum,  and  stops  the  passage,  causing  deafness.  The 
remedy  is  for  a  physician  to  syringe  with  warm  water  until 
the  lump  is  softened  and  comes  away,  when  hearing  returns  at 
once.  The  most  experienced  physicians  will  hardly  ever  use 
any  other  instrument  to  get  away  things  from  the  ear,  for  fear 
of  doing  damage  by  poking  among  the  delicate  structures. 


THE  EAR.  165 

Insects  dislike  the  ear-wax;  but  if  one  gets  in,  a  dro^)  or 
two  of  sweet  oil  will  dislodge  liim. 

A  violent  box  on  the  ear  lias  been  known  to  burst  the  drum 
and  cause  deafness.  It  is  not  a  safe  place  to  inflict  punish- 
ment. 

Persons  who  bathe  much  at  the  seaside  are  exposed  to  deaf- 
ness from  two  causes.  First,  the  surf  may  strike  directly  into 
the  ear  and  give  a  blow  to  the  drum ;  there  may  be  sand  in  the 
surf,  which  will  m.ake  matters  worse.  Then,  secondly,  people 
often  stay  in  too  long  and  get  chilled,  and  the  chill  is  very  apt 
to  "  strike  to  "  the  ear,  where  it  causes  inflammation.  There 
is  a  notion  that  people  cannot  take  cold  by  the  seashore ;  but 
slight  colds  which  affect  the  middle  ear  are  often  caught. 

Colds  in  the  throat  (sore  throat)  are  very  liable  to  affect  the 
middle  ear,  through  the  direct  passage  (the  Eustachian  tube) 
from  the  throat  to  each  ear,  up  which  inflammation  spreads. 
There  is  often  a  bad  sore  throat  in  scarlet-fever,  and  this  is 
one  of  the  commonest  causes  of  deafness  in  children. 

Children  are  sometimes  thought  to  be  stupid  or  careless, 
when  in  reality  they  are  only  deaf.  Some  deaf  ones  are  usu- 
ally found  in  every  school-room.  Some  catch  cold  easily,  and 
colds  settle  easily  in  their  ears ;  every  fresh  cold  of  this  sort 
is  liable  to  make  them  a  little  deafer ;  such  scholars  must  not 
sit  in  draughts  of  air.  It  is  far  easier  to  prevent  than  to  cure 
deafness  ;  the  curing  takes  a  long,  tedious  while.  As  preven- 
tives, wear  flannel,  avoid  colds,  avoid  bathing  in  surf,  or  div- 
ing, avoid  violent  winds,  or  draughts  in  rooms,  be  much  out  of 
doors,  and  grow  strong. 

Very  loud  noises,  as  the  firing  of  cannon,  may  cause  deaf- 
ness. Boiler-makers,  who  have  to  go  inside  of  a  boiler  while 
workmen  are  hammering  on  the  outside,  are  often  deaf. 

SYNOPSIS. 

The  outer  ear  is  called  the  concha.  The  passage  (meatus)  secretes 
wax  (cerumen),  and  leads  to  the  drum  (membrana  tympani).  Behind 
the  latter  is  a  small  cavity,  the  middle  ear,    containing  three  little 


166  PHYSIOLOGY. 

bones,  which  conduct  sound  from  the  drum  to  the  hmerear  (labyrmth), 
where  the  termhiations  of  the  auditory  nerve  are  arranged.  The 
Eustachian  tube  leads  from  the  middle  ear  to  the  throat. 

Sound  is  conducted  by  vibration  of  the  air,  or  of  solid  bodies.  All 
the  outer  parts  of  the  ear  are  formed  to  receive  and  conduct  the 
vibrations  to  the  inner  ear,  where  the  nerve  is  found  which  carries  the 
sensation  to  the  brain. 

It  is  extremely  improper  to  poke  or  push  articles  into  the  ear,  and 
may  be  dangerous  to  hearing.  Syringing  is  the  best  way  of  extracting 
things  from  the  passage.  Wax  is  thus  removed.  Blows  on  the  ear 
may  break  the  drum.  Sea-bathing  may  produce  a  chill,  or  the  surf 
may  directly  injure  the  drum;  deafness  is  occasionally  thus  caused. 
Colds  in  the  throat,  or  the  sore  throat  of  scarlatina,  may  spread  up  the 
Eustachian  tube  and  cause  deafness.  School  children  often  suffer  from 
this  complaint.     Loud  noises  may  cause  it. 

SUGGESTED   QUESTIOXS. 

Concha.  Meatus.  Drum.  Membrana  tympani.  ]\Iiddle  ear.  Bones 
Labyrinth.  Nerve  of  hearing.  Eustachian  tube.  Vibration.  Con- 
veyance of  sound.   Conveyance  of  vibration.   Conveyance  of  sensation. 

Dirt  in  the  ear.  Cleansing.  Wax.  Removal  of  substances.  In- 
sects. Blows.  Bathing.  Deafness:  some  causes.  Colds.  Sore 
throat.    Scarlatina.    Deafness  in  school  children.    Prevention.    Noise. 


CHAPTER   XL 

THE   TEETH. 

A  FULL  set  of  teeth.,  in  a  grown  person,  numbers  thirty-two. 
For  each  one  in  the  upper  jaw  there  is  a  similar  one  in  the 
lower.  Beginning  at  the  middle  line,  in  either  jaw,  we  can 
count  on  each  side  two  cutting-teeth  (inci'sors),  one  eye-tooth 


Ftg.  G3.  — First  and  second  sets  of  teeth  tos^ether.  1.  2.  incisors;  3,  canine;  4, 
5,  molars  —  all  of  these  belong  to  the  temporary  or  lirst  set,  while  the  per- 
manent set  is  seen  in  the  jaw  at  the  roots  of  the  first  set;  6,  11,  permanent 
molars. 

167 


168  PHYSIOLOGY. 

(canine;,  two  small  grinders  (bicuspids),  and  three  larger 
grinders  (molars).  The  last  molar  is  not  commonly  seen  until 
the  age  of  eighteen  or  twenty ;  it  is  called  the  wisdom-tooth 
(very  inappropriately),  and  may  not  appear  till  much  later  in 
life ;  it  is  apt  to  decay  sooner  than  the  others. 

Children  get  their  first  set  of  teeth  (the  "milk  teeth")  at 
various  periods,  beginning  from  the  fourth  to  the  sixth  month 
of  life.  This  set  comprises  twenty  teeth,  viz. :  eight  incisors 
or  cutting-teeth,  four  canines  or  eye-teeth,  eight  bicuspids,  or 
grinders,  with  two  roots. 

At  the  age  of  five  or  six  years  these  teeth  begin  to  drop  out, 
and  are  replaced  by  the  second  or  permanent  set.  The  jaw- 
bones, at  this  age,  present  the  appearance  shown  in  Fig.  63, 
where  both  sets  are  seen  to  be  present  at  once.  The  second 
set  grows  under  the  roots  of  the  first  set ;  as  they  grow,  they 
make  the  roots  gradually  disappear,  until,  by  the  time  the  new 
tooth  is  ready  to  push  through  the  gum,  the  root  of  the  old 
one  is  almost  wholly  gone,  and  the  tooth  hangs  loosely  to  the 
gums. 

In  many  children  the  teeth  of  the  second  set  grow  out  irreg- 
ularly. Some  are  blocked  or  pushed  aside  by  the  old  teeth, 
which  do  not  drop  out  soon  enough.  Some  grow  in  towards 
the  mouth  or  out  against  the  lips.  Teeth  may  be  too  large  for 
the  jaw ;  they  then  crowd  each  other,  making  the  line  of  teeth 
uneven.  Children's  mouths  should  be  examined  at  this  age  by 
the  dentist,  who  may  take  measures  to  make  room  for  the  teeth 
to  grow,  and  to  form  them  into  a  regular  and  handsome  line. 

The  character  of  the  food  eaten  by  an  animal  can  be  known 
from  the  form  of  his  teeth.  The  cutting  teeth,  with  edges  like 
chisels,  are  much  used  by  horses,  cattle,  deer,  sheep,  and  oth- 
ers which  crop  the  grass ;  they  are  large  and  strong  in  such 
animals,  and  still  more  so  in  those  which  gnaw,^ — rats  and 
mice,  squirrels,  beavers,  etc.     The  canines^  are  found  large 


1  Gnawing:  animals  are  called  rodents,  from  the  Latin  rodens,  gnawing. 

2  From  Latin  canis,  a  dog. 


THE   TEETH. 


169 


and  long  in  many  beasts,  as  cats,  lions  and  tigers,  dogs  and 
wolves,  which  require  such  teeth  in  catching  and  tearing  their 
prey.  Such  animals  have  much  smaller  front  teeth,  and  their 
back  teeth  are  not  used  for  grinding,  but  for  cutting  up  food. 
Any  one  may  notice  the  sharp  edges  of  the  back  teeth  of  a  cat 
or  dog,  and  how  they  fit  together  like  the  blades  of  scissors. 
Such  animals  do  not  grind  up  their  food,  but  quickly  chop  it 
up  and  swallow  it. 

G-rass-eating    animals    are    called   graminiv'ora,    and    grain- 
eaters,  graniv'ora.     For  grinding  their  food  they  possess  large, 
strong,  flat  back  teeth  ;  the  cow  and  horse 
are  good  examples. 

Man  possesses  all  three  classes  of  teeth, 
and  they  are  more  nearly  equal  in  size 
than  those  of  the  animals  mentioned.  He 
is  therefore  fitted  for  eating  a  great  variety 
of  food,  both  animal  and  vegetable. 

The  main  part  of  the  substance  of  a 
tooth  is  composed  of  a  material  called  den- 
tine, Avhich  resembles  bone.  The  dentine 
is  protected  by  a  rather  thin  layer  of  a 
much  harder  substance,  the  enamel,  which 
covers  all  the  parts  of  a  tooth  that  can 
be  seen ;  the  roots  are  covered  with  still 
another  substance,  the  cementum  (or  crusta 
petrosa) .  In  the  middle  of  every  tooth  is 
a  cavity,  the  pulp-cavity,  filled  with  soft 
tissue,  and  containing  nerves  and  blood- 
vessels. This  cavity  extends  into  the  roots ; 
at  the  tip  of  each  root  it  ends  in  a  small 
hole,  through  which  the  blood-vessels  and 
nerves  enter  the  tooth. 

The  crown  of  a  tooth  is  the  part  which  is  visible,  and  is 
covered  with  enamel.  The  necJc  is  the  part  just  above  the  gum. 
The  roots  are  firmly  wedged  into  the  jaws,  somewhat  as  a  nai] 
is  in  wood. 


Fig.  64.  —  Vertical  sec- 
tion of  a  bicuspid 
tooth,  magniiied. 


170  PHYSIOLOGY. 

The  enamel  gets  worn  off  from  the  crown  of  the  tooth,  at  the 
top,  generally  by  the  twentieth  or  thirtieth  year  of  age.  The 
dentine  then  comes  into  use,  and  commonly  answers  the  purpose 
as  well  as  the  enamel,  though  it  is  less  durable.  It  is,  however, 
liable  to  decay,  and  small  holes  or  cavities  are  often  formed  in 
it.  The  dentine,  in  some  persons,  is  sensitive  to  pain,  and  the 
cavities  in  it  are  apt  to  be  tender  and  cause  pain  when  a  person 
eats.  The  nearer  the  cavity  gets  to  the  pulp  of  the  tooth,  the 
more  sensitive  it  becomes ;  and  when  the  pulp-cavity  is  reached 
the  pain  is  severe,  since  the  very  nerves  themselves  are  laid 
bare. 

Filling  a  tooth  consists  in  clearing  out  the  rotting  dentine 
around  the  cavity,  and  then  inserting  some  preparation  which 
will  perfectly  fill  and  stop  up  the  cavity. 

The  advantage  of  filling  a  cavity  is,  that  the  decay  is  stopped 
at  that  point.  It  is  always  desirable  to  do  this  ;  even  young 
children  ought  to  have  their  teeth  kept  as  sound  as  possible, 
so  as  not  to  lose  any  until  Nature  is  ready  tc  furnish  the 
second  set.  If  the  first  ones  drop  out  too  soon,  it  may  happen 
that  the  second  ones,  when  they  come,  will  find  the  jaw  too 
small  for  them,  and  then  they  crowd  each  other,  producing  an 
ugly  appearance,  or  some  may  even  have  to  be  pulled  out  to 
give  room  for  the  rest. 

The  jaw  changes  a  good  deal  in  its  shape  and  proportions  at 
different  periods  of  life,  becoming  stronger  and  affording  more 
room  for  teeth  as  a  person  grows  from  infancy  to  adult  life. 
(See  Fig.  65.)  In  old  age,  or  ^^  second  childhood,"  after  the 
teeth  are  gone,  the  parts  about  the  sockets  shrink,  and  the  bone 
becomes  more  like  that  of  an  infant. 

Few  people  are  entirely  free  from  caries  of  the  teeth.  Even 
the  savage  Indians  of  our  country  are  subject  to  it,  and  suffer 
from  toothache.  Decayed  teeth  are  a  cause  of  foul  breath. 
They  sometimes  produce  the  most  horrible  neuralgia  of  the 
face.  And  there  is  this  further  disadvantage  in  losing  teeth, 
that  a  person  cannot  chew  so  well,  and  neither  enjoys  his  food, 
nor  digests  it  so  well. 


THE   TEETB. 


ITl 


Fio.  05.  —  Side  view  of  the  lower  jaw  at  different  periods  of  life.    1.  at  birth; 
2,  at  age  of  14;  3,  in  tlip  ndult ;  4,  in  old  age. 


172  PHYSIOLOGY. 

Some  persons'  teetli  are  so  poor  that  tliey  seem  to  decay  in 
sj^ite  of  the  best  care,  but  cleanliness  will  do  a  great  deal  in 
preventing  caries.  The  teeth  after  eating  remain  coated  with 
food,  which  is  liable  to  become  decomposed,  and  to  produce 
acids  that  eat  into  the  teeth.  The  proper  time,  therefore,  for 
cleaning  the  teeth,  is  after  meals.  A  toothpick  is  needed  to 
remove  bits  from  between  the  teeth,  and  then  a  brush,  dipped 
in  water  and  lightly  rubbed  on  soap,  is  to  be  used  both  inside 
and  outside.  Of  course,  the  purest  white  soap  is  required. 
Pumice  stone  powder  is  bad,  as  it  wears  away  the  teeth.  A 
dry  cloth  and  a  thread  may  be  required  by  some,  to  perform 
more  perfectly  the  office  of  toothbrush  and  toothpick. 

Some  persons'  mouths  are  always  sour.  This  is  an  un- 
healthy state,  partly  due  to  a  bad  stomach,  caused  by  eating 
unwholesome  food.  A  reasonable  amount  of  sweet  food  at 
meals  is  proper,  but  a  constant  nibbling  of  candy  between 
meals  is  sure  to  injure  the  stomach  and  teeth.  The  sugar 
is  not  all  swallowed,  either ;  some  of  it  adheres  around 
and  between  the  teeth,  and  very  soon  ferments,  turning  to  an 
acid  which  attacks  and  rots  the  teeth. 

There  is  in  soap  an  alkali  (soda)  which  corrects  or  "  neutral- 
izes" this  acid;  hence  soap  and  soda  are  useful  for  tooth- 
washes. 

Particles  of  food  adhering  to  the  teeth  or  sticking  in  crev- 
ices will  decay  quickly  and  produce  foul  breath,  with  injury  to 
the  teeth.  It  is  very  important  to  clean  the  teeth  so  as  to 
remove  all  the  particles  of  food. 

A  toothpick  of  quill  or  wood  should  be  used  after  each  meal. 
Even  better  than  a  toothpick  is  a  piece  of  waxed  thread,  a  waxed 
floss-silk,  or  a  piece  of  a  small  rubber-ring.  (Toothpicks 
should  not  be  used  in  company  or  carried  about  in  the  mouth.) 

The  toothbrush  is  more  effective  when  rubbed  up  and  down 
instead  of  across.  Soap  is  useful  with  the  brush.  As  a  tooth- 
powder,  fine  precipitated  powder  of  chalk  is  best ;  it  not  only 
helps  to  remove  substances  from  the  teeth,  but  being  an  anti- 
acid  it  corrects  the  sourness  of  the  mouth. 


TUE   TEETH  173 


SYNOPSIS. 


The  teeth  in  the  upper  and  lower  jaws  correspond ;  the  right  and 
left  sides  also  correspond.  Reckoned  from  the  middle,  the  adult  has 
8  incisors,  4  canines,  8  bicuspids,  and  12  molars  =  32.  The  wisdom- 
teeth  come  latest,  and  often  decay  early.  The  first  set  comprises  8 
incisors,  4  canines,  8  bicuspids,  which  are  replaced  by  permanent  teeth 
after  the  age  of  five.  The  new  ones  grow  under  the  roots  of  the  old, 
which  gradually  waste  aw^ay  to  give  room  for  the  new  growth.  If  this 
process  goes  on  ii-regularly,  the  teeth  may  grow  in  the  wrong  direc- 
tion. They  may  be  too  large  for  the  jaw;  or  the  jaw  may  be  too 
small  for  the  usual  size  of  tooth.  The  dentist  should  examine  chil- 
dren's jaws  to  prevent  the  deformity  caused  by  these  circumstances. 

The  front  teeth  are  strong  in  the  herbivorous  animals,  still  more  so 
in  the  rodents.  The  canines  are  powerful  in  the  carnivora,  as  lions  and 
wolves.  The  back  teeth  are  large  and  flat  in  the  herbivora,  sharp  like 
scissors  in  the  carnivora.  In  man,  all  are  developed  in  nearly  equal 
proportion,  to  suit  his  mixed  diet. 

The  substance  of  a  tooth  is  dentine.  The  roots  are  covered  with 
cementum,  the  crown  with  enamel.  The  central  pulp-cavity  contains 
blood-vessels  and  nerves,  and  extends  to  the  end  of  the  root.  When 
the  enamel  is  worn  off  from  a  part,  decay  is  more  likely  to  occur. 
Cavities  in  the  dentine  are  j)ainful  in  proportion  as  they  are  deep; 
filling  relieves  pain  and  sto^DS  decay ;  the  decayed  material  is  removed 
before  filling.  Filling  cavities  in  the  first  set  is  to  be  recommended ; 
if  they  drop  out  prematurely  the  jaw  fails  to  get  full  growth. 

Caries  occurs  among  all  nations.  It  causes  foul  breath,  toothache, 
neuralgia,  and  dyspepsia.  Cleanliness  is  the  best  preventive,  though 
not  always  effectual ;  it  comprises  cleansing  with  brush  and  soap, 
cloth,  thread,  and  toothpick;  carefulness  in  diet  (no  sweets  allowed 
out  of  meals)  ;  and  the  use  of  antacids  when  needed. 


SUGGESTED   QUESTIONS. 

Number  of  teeth  of  each  sort  in  adult  set ;  in  first  set.  Wisdom- 
teeth.  Ages  at  which  teeth  appear.  Process  of  exchange  of  first  for 
second  set.  Irregularities  in  the  process;  consequences,  remedies. 
Form   and  relative  size  of  the  different  classes  of  teeth  in  different 


174  PHYSIOLOGY. 

families  of  animals;  uses  of  such  special  forms;  in  man.  Dentine, 
enamel,  cementum,  pulp-cavit}',  crown,  root,  neck,  nerves,  blood-vessels. 
Decay,  first  step;  sensitiveness;  filling — the  process,  its  advantages, 
and  the  age  for  doing  it.  Premature  loss  of  first  teeth ;  effects. 
Savages.  Effects  of  caries.  Time  for  cleansing  the  teeth.  Instru- 
ments to  be  used.  Powders  or  washes.  Particles  of  food.  Sweet 
food,  or  candy.     Antacids. 

NOTES   FOR   TEACHERS. 

The  study  of  the  teeth  of  animals  can  be  made  extremely  interest- 
ing. The  skull  of  one  of  the  carnivora  (dog,  cat),  one  of  the  her- 
bivora  (sheep,  goat),  and  one  of  the  rodents  (rat,  squirrel),  can  be 
prepared  for  use  by  removing  the  ^ soft  parts  with  a  knife,  and  soak- 
ing the  bone  in  water  five  or  six  weeks  until  the  remaining  bits  of 
tissue  can  easily  be  removed  by  cleaning.  In  winter,  keep  in  a  warm 
place  while  macerating.  An  adult  animal  should  be  chosen.  The 
comparison  of  these  specimens  with  one  another  and  with  the  human 
skull  cannot  fail  to  be  interesting. 

In  Professor  Bowditch's  little  manual  ("Hints  for  Teachers  in 
Physiology  ")  the  subject  of  the  teeth  is  treated  at  some  length  and 
very  practically. 


CHAPTEK   XII. 

STIMULANTS    AND    NAEOOTIOS. 

ALCOHOL   AND    ALCOHOLIC    BEVERAGES. 

Alcohol  is  a  clear  liquid  looking  like  Avater ;  it  burns  very 
easily,  and  gives  a  liot  flame. 

It  is-  made  from  various  substances  containing  sugar  or 
starch,  by  fermentation  and  distillation. 

The  juice  of  grapes  contains  much  sugar.  If  allowed  to 
stand,  the  juice  will,  after  a  while,  become  full  of  small 
bubbles  of  carbonic  acid  gas  (like  soda  water),  and  its  taste 
will  change ;  these  are  signs  that  the  sugar  is  turning  to 
alcohol.  When  fermentation  is  over,  the  liquid  is  wine,  and 
contains  alcohol  in  varying  proportions  ^from  four  to  fourteen 
per  cent  or  thereabouts),  according  to  the  amount  of  sugar. 
Cider  is  made  in  the  same  way  from  apple  juice,  but  the  sugar 
is  incompletely  changed,  and  the  percentage  of  alcohol  is 
small  —  about  five  parts  in  one  hundred.  This  process  is  fer- 
mentation.    Beer  is  a  fermented  drink  made  from  grain. 

Grain,  potatoes,  or  similar  food-substances,  when  mashed 
with  water,  will  ferment  in  like  manner.  After  fermentation 
is  over,  the  liquid  is  placed  in  metal  boilers  with  long  tubes 
attached,  called  stills,  and  heated:  the  steam  that  conies  out 
consists  of  the  vapors  of  water  and  alcohol  mixed,  and  both 
are  condensed  by  cooling  in  the  pipe,  where  they  form  drops 
of  fluid.  This  process  of  heating  and  condensing  is  distillation, 
and  the  product  is  distiUed  sjoirit,  consisting  of  alcohol  mixed 
with  water,  and  various  other  substances  in  very  small  quan- 

175 


176  PHYSIOLOGY. 

titles.  Ill  the  common  forms  of  spirit  (rum,  brandy,  whiskey, 
gin),  about  one-half  is  alcohol  and  one-half  water. 

Pure  alcohol  is  rarely  seen ;  that  which  is  used  for  burning 
in  lamps  contains  some  water.  It  has  various  useful  proper- 
ties in  the  arts  and  medicine,  owing  to  its  power  of  dissolving 
many  substances  (gums,  varnishes,  certain  drugs)  which  water 
will  not  dissolve.  In  science,  it  is  useful  for  preserving  speci- 
mens in  natural  history,  as  fishes  and  snakes. 

When  used  as  a  beverage,  or  drink,  alcohol  is  not  taken  un- 
mixed except  by  savages :  its  taste  is  altogether  too  hot  and 
disagreeable  for  civilized  man.  The  drinks  which  contain  it 
vary  in  strength  (as  above  noted)  from  about  one-twentieth 
alcohol  to  about  one-half.  Their  effects  are  not  exactly  alike ; 
but  they  all  possess,  in  proportion  to  their  strength  in  alcohol, 
a  certain  well-known,  poisonous  effect,  which  is  called  intoxi- 
cation,^ or  drunkenness.  This  effect  consists  (in  brief)  of  a 
weakening  of  the  powers  of  the  mind  and  of  the  muscles. 

A  sober  person,  sitting  with  others  who  are  drinking,  notices 
that  they  seem  in  gay  spirits.  Presently  they  begin  to  say 
foolish  things,  and  laugh  at  them  as  if  they  were  witty.  They 
are  apt  to  say  many  things  which  they  afterward  wish  they 
had  not  said.  The  Latin  proverb  "  In  vino  Veritas  "  (there  is 
truth  in  wine)  means  that  a  person  who  has  a  secret  to  keep 
is  apt  to  let  it  out  if  he  is  drinking.  Many  persons  have  a 
bad  side  to  their  character,  which  they  are  able  to  control 
when  sober,  but  when  drunk  they  seem  not  to  care  about  right 
or  wrong.  Some  use  vile  language,  some  become  quarrelsome, 
or  wildly  furious,  and  fight  with  their  best  friends,  or  beat 
their  wives  and  children.  Men  who  are  good  and  peaceable 
while  sober  may  be  changed  into  wild  savages  by  drink. 

One  other  change  is  that  the  hand  is  less  steady,  and  the 
legs  less  firm ;  the  gait  becomes  staggering  and  tipsy ;  and  at 
the  end  one  is  quite  helpless,  and  lies  perfectly  stupid  on  the 
ground.     While  in  this   state  of  "dead-drunkenness,"  which 

1  From  a  Greek  word  meaning  "poison." 


STIMULANTS  AX  J)   NAIWOTICS.  177 

resembles  a  fit  of  apoplexy^  the  stomach  often  casts  up  what 
has  been  eaten  and  drunk.  In  this  condition  the  heart  keeps 
on  beating  and  the  lungs  breathing ;  but  cases  have  occurred 
in  which  they  have  come  to  a  stop  under  the  influence  of  the 
alcohol,  and  death  has  ensued. 

After  a  fit  of  drinking,  a  man's  stomach  is  in  a  very  bad 
condition ;  he  cannot  eat,  he  feels  sick  all  over,  his  head  aches, 
he  is  miserable.  At  such  times  the  stomach,  if  seen,  Avould 
appear  very  red,  almost  inflamed. 

With  most  poisons,  a  person  usually  feels  sick  or  distressed 
or  in  pain.  With  alcohol,  the  first  feeling  is  usually  pleasant, 
and  that  is  noticed;  but  the  foolishness,  the  weakness,  the 
neglect  of  duty,  the  loss  of  control  over  the  muscles,  are  not 
noticed,  but  begin  gradually  and  unperceived.  ]\Iany  persons 
are  *'not  quite  themselves"  a  good  deal  of  the  time,  from 
drinking,  but  are  not  aware  that  they  ever  are  "  affected "  at 
all,  though  their  friends  see  it  clearly. 

One  of  the  surest  ways  of  forgetting  how  much  one  has  taken 
is  to  drink  in  company,  or  because  another  invites  and  pays. 
It  is  as  childish  to  drink  when  you  are  asked  as  it  would  be 
to  eat  because  you  are  asked,  without  regard  to  hunger. 

It  is  a  proof  of  the  bad  effect  of  alcohol  on  the  mind,  that 
in  situations  where  great  care  is  required  —  as  among  railway 
conductors  and  engineers  —  no  drinking  man  is  employed.  A 
very  little  drink  may  take  away  the  fineness  of  the  sight  or 
hearing,  or  make  a  man  slow  or  careless,  or  his  hand  unsteady ; 
and  the  worst  is,  the  man  does  not  know  it. 

People  differ  much  in  their  power  to  resist  these  poisonous 
effects  of  spirituous  liquor  and  beer.  Some  have  such  "strong 
heads"  that  they  seem  able  to  take  unlimited  quantities. 

Many  consume  a  good  deal,  but  do  not  become  drunk ;  they 
drink  a  little  at  a  time,  and  are  all  the  time  under  the  influ- 
ence of  liquor  to  a  slight  extent.  It  is  probable  that  this  prac- 
tice injures  the  constitution  more  than  occasional  fits  of 
intoxication;  it  breaks  down  the  health  in  a  slow  way,  un- 
perceived by  the  sufferer  at  first. 


178  PHYSIOLOGY. 

Thus,  in  various  ways,  we  find  that  there  may  be  danger, 
even  when  a  person  seems  to  be  moderate  in  his  habit  of 
drinking.  It  is  not  always  easy  for  a  person  to  decide  whether 
he  is  moderate  ;  his  neighbors  may  see  more  clearly  than  he 
does,  and  may  notice  things  about  him  which  he  cannot  see. 
Or,  a  man  may  be  so  accustomed  to  the  use  of  alcoholic  drinks, 
that  even  large  quantities  may  never  make  him  positively  in- 
toxicated. To  tell  the  truth,  both  these  classes  of  men  are 
really  in  some  degree  drunkards.  Neither  of  these  classes 
is  capable  of  resisting  the  effects  of  long-continued  drench- 
ings  with  the  deleterious  fluid ;  sooner  or  later,  the  powerful 
laborer,  no  less  than  the  sedentary  clerk,  succumbs. 

It  seems  also  to  be  a  fact  that  many  persons  have  a  ten- 
dency to  increase  gradually  the  amount  taken.  This  is  one 
of  the  worst  dangers  attendant  on  the  use  of  alcoholic  drinks. 

In  prescribing  stimulants,  a  careful  physician  will  bear  in 
mind  the  possibility  that  his  patient  may  continue  their  use 
when  they  are  no  longer  necessary ;  for  the  taste  is  easily 
acquired,  and  the  ill  effects  are  likely  to  be  overlooked. 

Americans  are  generally  affected  more  by  a  given  quantity 
of  drink  than  the  inhabitants  of  Northern  Europe  are  by  the 
same  amount.  It  seems  to  be  more  injurious  to  us  than  to 
them.  It  is  thought  that  the  climate  is  the  cause  of  this 
difference. 

The  habits  of  life  in  Europe  are  in  many  ways  different 
from  ours.  Some  of  the  nations  use  wine  as  commonly  as  we 
use  water,  as  in  Italy,  Spain,  and  Greece.  These  nations  have 
small  appetites  for  food,  and  consume  much  less  at  a  meal 
than  we  do.  In  Germany  and  parts  of  France  beer  is  taken 
regularly  as  a  drink  by  almost  everybody.  A  very  large  num- 
ber of  the  working  classes,  in  all  these  countries,  really  cannot 
get  enough  to  eat ;  an  American  laborer  would  look  with  pity 
on  their  regular  diet,  consisting  chiefly  of  bread,  cheese,  cabbage, 
and  a  little  sausage,  with  fresh  meat  perhaps  once  a  week,  but 
with  nothing  so  expensive  as  butter.  In  some  regions  the 
peasants  mix  the  ground  bark  of  trees  with  their  bread,  for 


STIMULANTS   AND   NARCOTICS.  170 

want  of  sufficient  flour.  A  little  cheap  beer  or  wine  goes  a 
great  way  with  such  people  in  making  their  wretched  food 
palatable.  They  regard  it  as  Ave  do  tea  —  as  a  part  of  their 
regular  diet.  Xowhere  in  our  country  do  laborers  have  that 
excuse  which  these  people  have  for  using  alcoholic  drink. 

At  the  same  time,  drunkenness  does  a  great  deal  of  harm 
all  over  Northern  Europe  and  in  Great  Britain.  It  may  be 
called  a  national  vice  in  those  countries.  If  they  can  bear 
more  than  we  can,  they  nevertheless  suffer  from  taking  too 
much.  And  this  has  always  been  known  to  be  the  danger,  for 
drunkenness  with  wine  is  mentioned  as  a  very  evil  thing  by 
Solomon,  who  lived  nearly  three  thousand  years  ago. 

The  effects  already  described  are  produced  by  all  kinds  of 
alcoholic  drinks.  But  there  is  a  difference  in  the  quality  of 
liquors,  due  to  the  presence  of  certain  flavoring  matters,  which 
are  often  really  medicines,  unfit  to  be  used  by  well  persons. 
The  difference  in  the  taste  of  rum,  gin,  and  whiskey  is  due  to 
such  flavoring.  Wine,  beer,  cider,  each  contain  peculiar  sub- 
stances. Beer  has  a  special  stupefying  ingredient  (lupulin) 
which  comes  from  the  hops  used  in  making  it.  Cider  in  excess 
will  make  people  drunk. 

Strong  drink  is  a  cause  of  insanity ;  about  ten  'per  cent  of 
the  cases  in  asylums  being  due  to  this  cause. 

A  person  furiously  drunk  is  as  truly  insane,  for  the  time, 
as  the  worst  maniac. 

Persons  who  have  kept  up  the  habit  of  drinking  much  are 
apt  to  have  an  attack  of  mania  a  potu  ("drink-madness"), 
otherwise  called  delirium  tremens.  In  this  disease  the  mind 
is  wild,  full  of  fear  and  of  false  imaginations;  the  patient 
thinks  he  sees  all  kinds  of  horrid  creeping  things,  snakes  and 
rats,  around  the  room  and  on  the  bed ;  he  tries  to  get  away, 
and  would  jump  from  the  window  if  not  prevented.  Death 
is  not  uncommon  in  this  complaint. 

Another  form  of  insanity  is  met  with  in  many  persons  who 
seem  to  be  well  most  of  the  time.  Once  in  a  month  or  two, 
a  very  strong  desire  to  drink  comes  over  them,  and  it  seems 


180  PHYSIOLOGY. 

impossible  for  them  to  avoid  drinking  unless  they  are  locked 
up  in  some  asylum;  they  get  drunk  and  stay  so  for  many 
days,  after  which  they  recover  and  go  about  their  business, 
and  are  sober  until  the  attack  seizes  them  again. 

It  has  been  much  questioned  whether  alcohol  can  be  con- 
sidered as  a  food.  The  point  is  not  discussed  in  the  present 
work.  At  all  events,  it  appears  to  have  the  curious  power  of 
taking  the  place  of  food  to  some  extent. 

There  are  other  drugs  which  have  the  same  power. 

The  drug  coca  is  used  by  South  American  Indians  on  very 
long  marches,  and  in  severe  work  in  the  mines,  and  it  keeps 
up  their  strength  for  days  while  they  have  hardly  any  food ; 
but  coca,  if  taken  too  long  and  too  freely,  makes  a  man  a 
wretched,  broken-down  invalid.  How,  when,  and  in  what 
quantities,  alcoholic  drinks  may  properly  be  used,  is  an  ex- 
tremely difficult  question.  There  is  one  thing  which  seems 
certain,  —  that  spirits  are  more  hurtful  than  wine  and  beer ; 
and  yet,  even  in  countries  where  no  spirits  are  used,  many 
people  are  injured  by  too  much  wine,  and  the  same  was  true 
in  the  times  before  alcohol  and  spirits  were  discovered,^  and 
wine  was  the  only  drink  of  the  kind  known. 

Another'certain  thing  is  that  spirituous  drinks  cause  great 
injury  to  the  morals,  and  much  crime.  Men  of  great  experi- 
ence, judges,  and  keepers  of  prisons,  say  that  one-half,  or  more, 
of  the  crimes  they  have  to  punish  are  caused  by  drinking.  It 
is  well  known  that  many  men  are  made  j)Oor  by  drinking. 
Whole  nations  of  strong,  healthy  people,  like  our  North 
American  Indians,  have  been  brought  down  by  drunkenness 
from  their  former  condition  of  free,  brave,  faithful  men,  to 
their  present  wretched  state  of  vice  and  laziness,  in  which 
they  are  often  a  curse  to  all  their  neighbors.^ 


1  Alcohol  was  discovered  about  1000  a.d. 

2  This  is  the  case  more  especially  with  those  Indians  that  have  long  been 
settled  near  the  whites,  who  supply  them  with  rum.  Indians  living  where 
they  can  get  no  rum  are  still  in  their  former  condition,  hardy,  brave,  and 
active. 


STIMULANTS   AND   NATICOTICS.  181 

The  following  are  among  tlie  known  ellec^ts  of  alcohol  on 
the  organs  and  tissnes  :  — 

At  the  beginning,  the  heart  beats  (xuicker  and  with  more 
force;  also,  the  blood-vessels  become  larger,  and  the  current 
somewhat  slower  in  them.  The  skin  is  therefore  reddened. 
This  reddening,  in  habitual  drinkers,  may  become  permanent. 
These  are  bad  effects;  ^jhysicians  can  employ  alcohol,  how- 
ever, for  good  purposes,  in  cases  where  there  is  danger  to  life 
from  great  weakness  of  the  heart. 

The  rush  of  blood  to  the  skin,  caused  by  spirit,  makes  a 
person  feel  warm.  This  feeling  is  deceitful ;  the  spirit  brings 
no  real  warmth.  It  is  in  the  highest  degree  dangerous  to  use 
spirits  when  men  are  exposed  to  cold  and  in  danger  of  freez- 
ing. Arctic  expeditions  are  now  conducted  on  total-abstinence 
principles.  The  truth  is,  that  alcohol  cools  the  blood,  and  this 
can  be  proved  in  fevers  by  measuring  the  temperature  with 
the  thermometer.  The  proper  use  of  spirits  is  to  bring  back 
strength  to  a  chilled  and  exhausted  person,  for  a  few  minutes, 
so  that  he  may  be  able  to  rouse  himself  up  and  walk  to  a 
house,  where  he  can  get  real  warmth  from  a  real  fire. 

The  coats  of  the  blood-vessels  are  apt  to  become  slowly 
injured  and  weakened  by  the  effects  of  alcoholic  drinks. 
When  this  is  the  case,  the  arteries  sometimes  burst,  which 
may  cause  death. 

The  stomach  is  often  affected;  sometimes  the  appetite  is 
improved,  as  physicians  know ;  at  other  times  it  is  injured,  as 
is  often  the  case  with  old  soakers  who  seem  to  live  on  drink 
instead  of  food.  This  latter  state  is  a  very  dangerous  one, 
and  is  likely  to  cause  injury  to  the  arteries,  kidneys,  heart,  or 
liver;  because  alcohol  does  not  really  feed  these  organs  as 
food  does,  but  gives  them  an  unwholesome  support. 

A  certain  disease  of  the  liver,  which  is  slow  but  fatal,  has 
long  been  considered  as  due  to  spirit-drinking ;  it  is  called  the 
"gin-drinker's  liver";  another  name  is  the  "hob-nail  liver," 
from  the  peculiar  appearance  of  the  organ,  as  if  studded  with 
heavy  nail-heads. 


182  PHYSIOLOGY. 

The  kidneys  are  often  affected  with  a  slow  and  fatal  dis- 
order called  Bright's  Disease,  which  has  many  causes,  one  of 
which  is  excess  in  alcoholic  drink. 

Gout  makes  the  joints  swell  up,  and  gives  horrible  pain.  It 
is  made  worse  by  some  sorts  of  alcoholic  drink ;  and  these 
drinks,  with  other  excesses  in  eating  and  drinking,  are  chief 
causes  of  gout. 

All  that  may  be  said  of  the  injury  caused  by  alcohol  applies 
with  great  force  to  young  persons.  The  system  is  doubly 
injured  by  excesses  in  youth.  A  boy's  frame  is  not  able  to 
stand  such  rough  work  as  a  man's,  neither  is  his  system  as 
capable  of  enduring  the  effects  of  alcoholic  drink  as  a  man's 
may  be.  Persons  who  could  stand  the  effects  of  tobacco  and 
alcohol  in  adult  life  may  be  permanently  injured  by  their  use 
in  boyhood.  This  is  one  reason  —  that  youth  has  less  power 
to  resist  poisons  or  bad  influences  of  any  sort  than  adult  life 
has.  The  other  reason  is,  that  the  forces  of  a  youth's  system 
are  all  needed  to  help  in  growing ;  and  alcohol  may,  and  often 
does,  check  the  growth  of  young  animals.  The  younger  a 
person  is,  the  more  he  is  harmed ;  and  for  little  children,  it  is 
as  truly  a  poison,  and  a  waster  of  life,  as  opium  is. 

Mention  has  been  made  of  the  use  of  alcoholic  drinks  in 
medicine.  It  is  not  proper  to  discuss  this  matter  in  a  book 
like  the  present.  It  must  be  left  to  physicians  to  decide,  in 
each  case,  whether  they  are  required.  It  seems,  however,  to 
be  a  fact  that  it  is  less  used  for  these  purposes  than  was  the 
case  ten  or  twenty  years  ago. 

TEA,    COFFEE,    CHOCOLATE. 

There  are  very  few  nations  in  the  world  that  do  not  use  one 
or  more  of  these  drinks.  The  Chinese  have  used  tea  for  thou- 
sands of  years,  and  they  seem  at  present  to  be  a  strong  and 
hardy  race,  perhaps  the  most  industrious  on  the  globe. 
Chocolate  is  the  favorite  drink  of  the  people  of  the  hot  parts 
of  America.  Coffee  is  very  much  used  by  the  Mohammedan 
nations,  and  among  all  civilized  races. 


STIMULANTS   AND   NARCOTICS.  188 

These  drinks  do  not  art'ect  people  in  just  the  same  way. 
They  have  different  ^fiavors;  and  these  flavors,  or  odors,  are 
due  to  the  presence  of  certain  volatile  oils.  To  form  a  clear 
idea  of  what  a  volatile  oil  is,  the  reader  may  lightly  scrape  the 
rind  of  an  orange  with  a  knife,  so  as  to  break  the  small  yellow 
globules,  or  cells,  and  notice  that  there  is  an  oily  feeling  to  the 
fluid  which  comes  from  the  cells.  There  is  also  a  strong  odor 
to  this  orange  oil :  all  volatile  oils  have  strong  odors.  When 
hot  water  is  poured  on  coffee,  tea,  or  cocoa,  a  part  of  the  oils 
is  extracted  by  the  water,  and  gives  the  flavor.  As  these  oils 
differ  from  one  another,  the  drinks  have  slightly  different 
effects,  though  the  greater  effect  is  that  due  to  the  caffein.  In 
addition  to  the  volatile  oils,  these  articles  contain  a  substance 
which  in  large  quantities  is  properly  a  poison,  but  in  the  small 
amounts  found  in  the  beverages  is  generally  harmless.  This 
substance  is  called  thein,  caffein,  and  cocoin :  it  is  the  same 
under  each  name. 

One  effect  of  tea  and  coffee  seems  to  be,  that  if  a  person 
takes  a  good  deal  he  can  apparently  do  with  less  food.  In  this 
respect  they  are  like  alcoholic  drinks.  And  they  do  harm 
when  they  take  the  place  of  food.  Many  persons  have  the 
very  bad  habit  of  making  a  meal  of  a  cup  of  tea  or  cott'ee, 
either  because  they  have  not  time  to  eat,  or  because  they  have 
not  money  to  pay  for  food,  or  because  they  have  no  appetite. 
The  drink  makes  them  feel  stronger  for  the  time,  and  they  do 
not  feel  the  need  of  food  ;  but  that  is  only  a  Avay  to  cheat 
nature.  Nature,  however,  will  not  be  cheated,  and  when  food 
is  not  taken,  the  system  will  suffer. 

The  effects  of  drinking  too  much  tea  are  various.  Many 
suffer  from  headache  ;  many  from  constipation ;  many  from 
nervousness  or  bad  temper.  Dyspepsia  is  frequent.  Palpita- 
tion of  the  heart  is  not  uncommon,  and  is  a  very  distressing 
feeling.  Coffee  is,  in  general,  similar  in  its  action.  Cocoa  and 
chocolate  affect  some  persons  in  the  same  way ;  but  there  is  so 
much  nourishment  (of  a  rich,  fatty  sort,  besides  albuminoid  mat- 
ters) in  these  latter  drinks  that  they  are  usually  wholesome. 


184  PHYSIOLOGY. 

There  is  a  good  side  to  the  question,  however.  Coffee  has 
been  found,  in  armies  and  on  ships,  to  have  a  great  power  of 
keeping  up  the  strength  when  men  are  tired  and  cold,  as  sailors 
and  soldiers  often  have  to  be.  It  is  altogether  superior  to 
alcoholic  drinks,  in  such  cases.  The  Russians,  who  know  from 
experience  the  effects  of  a  cold  climate,  drink  a  great  deal  of 
tea.  A  friend  of  the  writer's  has  told  him  how,  after  travel- 
ling all  day  in  dog-teams  across  the  snow,  he  has  drunk  a  dozen 
cups  of  hot  tea  at  night,  and  has  "  turned  in  "  and  slept  like  a 
top  till  morning.  Tea  and  coffee  do  not  make  people  drunk 
and  crazy ;  they  do  not  rouse  up  low  and  immoral  thoughts ; 
they  do  not  make  people  break  the  laws,  as  alcoholic  drinks 
sometimes  do. 

Tea  and  coffee  are  generally  harmless  —  or  they  may  be 
beneficial  —  to  persons  who  live  a  hardy  out-door  life  with 
much  muscular  exercise.  They  are  frequently  harmful  to 
those  who  live  mostly  in-doors,  taking  little  exercise. 

It  would  be  much  better  for  persons  under  adult  age  to  be 
without  these  drinks.     There  are  exceptions,  but  very  few. 


TOBACCO. 

Tobacco  contains  an  extremely  poisonous  volatile  substance 
called  nicotine,  of  which  "mild"  tobacco  contains  less  than 
stronger  sorts.  It  is  very  dangerous  to  swallow  tobacco. 
Chewers  usually  spit  out  the  juice ;  it  would  make  them  sick 
to  swallow  it.  Some  effect  is  produced  by  the  small  amount 
which  enters  the  system  by  soaking  through  the  mucous  mem- 
brane of  the  mouth. 

The  smoker  usually  tries  to  get  rid  of  a  part  of  the  nicotine. 
By  the  Orientals,  this  is  accomplished  by  passing  the  smoke 
through  water,  which  takes  out  a  great  deal  of  nicotine,  and 
gives  a  mild  effect.  Our  smokers  throw  away  the  cigar-stubs, 
in  which  the  substance  accumulates.  The  North  American 
Indians  did  exactly  the  opposite  in  their  grand  councils ;  they 


STIMULANTS  ANIJ   NABiJOTICS.  185 

ecouomized  the  effects  by  swallowing  a  little  smoke,  and  pass- 
ing the  pipe  to  the  next  man. 

It  is  often  said  by  smokers  that  cigarettes  are  more  injurious 
than  other  forms  of  using  tobacco. 

Every  one  knows  the  sickness  which  the  first  use  of  tobacco 
causes.  After  a  while  the  system  gets  used  to  it,  and,  indeed, 
cannot  do  without  it :  it  is  terribly  uncomfortable  to  have  to 
give  up  tobacco,  if  one  has  the  habit. 

Does  tobacco  do  harm  ?  To  many  j)ersons  it  seems  to  do  no 
harm.  That  which  at  first  made  a  person  feel  as  if  he  were 
dying,  soon  gives  no  discomfort,  and,  in  fact,  makes  one  feel 
pleasantly.  Smokers  say  that  it  makes  them  feel  comfortable 
when  they  are  tired  with  hard  work.  The  x^ersons  who  are 
most  injured  are  those  who  do  no  hard  bodily  work.  Many 
such  are  undoubtedly  injured.  Some  of  the  chief  effects  are, 
in  such  cases,  a  kind  of  weakness,  a  nervousness,  and  trouble 
with  the  stomach.  It  is  not  uncommon  to  find  persons  suffer- 
ing with  palpitation  of  the  heart,  caused  by  tobacco.  Others 
have  weak  sight  from  the  same  cause.  The  general  effect 
seems  to  be,  to  weaken  the  nervous  system. 

For  young  persons,  not  grown  up,  the  same  thing  may  be 
said  as  in  the  case  of  alcoholic  drinks,  tea,  and  coffee.  They 
will  probably  grow  up  stronger  in  muscle,  more  able  to  run, 
jump,  box,  and  row,  if  they  grow  up  without  these  things.  Of 
tobacco,  in  particular,  it  is  noticed  that  boys  who  use  it  are  apt 
to  become  lazy ;  they  like  better  to  huddle  together  in  some 
warm  corner  than  to  rush  about  after  the  football.  It  is  apt 
also  to  make  them  a  little  stupid  while  they  are  using  it. 


APPENDIX  T. 

The  following  extracts  are  taken  from  the  writings  of  medi- 
cal men  of  the  highest  reputation  for  scientiiic  knowledge  and 
clear  judgment.  They  may  be  regarded  as  unprejudiced  state- 
ments of  fact,  made  upon  the  best  authority,  and  with  the 
best  light  that  our  present  scientiiic  knowledge  imparts. 

ALCOHOLIC  BEVERAGES. 

From  "  Treatise  on  Food  and  Dietetics,"  by  F.  W.  Pavy,  Fellow  of  the  Royal  College  of 
Physicians,  and  Lecturer  on  Physiofogy  at  Guy's  Hospital,  London.  2d  edition,  1S81 
(Wood  &  Co.),  p.  237. 

Alcoholic  beverages,  taken  in  moderate  quantity,  increase  the  activ- 
ity of  the  circulation.  The  heart  beats  more  rapidly.  The  pulse 
becomes  not  only  more  frequent,  but  at  the  same  time  fuller.  The 
arteries  dilating  allow  the  blood  to  flow  more  freely  to  the  capillaries, 
thus  leading  to  turgescence  of  the  small  cutaneous  vessels,  and  account- 
ing for  the  flushing  of  the  face  that  is  noticeable.  .  .  .  The  warm 
blood  from  the  interior,  circulating  more  freely  over  the  surface, 
imparts  a  temporary  glow  to  external  parts;  but  the  outside  is 
warmed  at  the  expense  of  the  inside.  The  amount  of  the  urinary 
secretion  is  increased,  the  appetite  augmented,  digestion  promoted, 
the  nervous  system  stimulated,  and  the  mental  faculties  exhilarated. 
In  moderate  quantities,  in  short,  observation  shows  that  the  alcoholic 
beverages  act  as  a  general  stimulant. 

Dr.  Parkes  has  submitted  to  direct  investigation  the  question 
whether  the  effect  of  alcohol  is  to  increase  or  diminish  the  facility 
v/ith  which  work  is  performed.  In  one  of  his  series  of  observations  a 
soldier  passed  a  period  of  three  days  performing  a  certain  amount  of 
work  without  the  use  of  brandy;  and,  after  three  days  of  rest,  another 
period  of  three  days  of  work  with  twelve  ounces  of  brandy  per  diem, 
administered  in  four-ounce  doses,  at  10  a.m.,  2  p.m.,  and  6  p.m.  The 
man  was  requester!  to  observe  as  closely  as  he  could  whether  he  did 
the   work  better  with  or  without  the  brandy.     He  commenced   the 

187 


188  APPENDIX, 

brandy  period,  it  is  stated,  with  the  belief  that  the  brandy  would 
enable  him  to  perform  the  work  more  easily,  but  ended  with  the  oppo- 
site conviction.  The  work  performed  was  chiefly  done  in  the  two 
hours  immediately  succeeding  each  dose  of  brandy.  The  two  hours' 
work  after  the  first  four  fluid  ounces  appeared  to  be  accomplished 
equally  well  with  and  without  the  brandy.  The  man,  it  is  said,  could 
tell  no  difference  except,  to  use  his  own  words,  "the  brandy  seemed 
to  give  him  a  kind  of  spirit  which  made  him  think  he  could  do  a  great 
deal  of  work,  but  when  he  came  to  do  it  he  found  he  was  less  capable 
than  he  thought."  After  the  second  four  ounces  of  brandy,  at  2  p.m., 
he  felt  hot  and  thirsty,  but  on  the  first  two  days  thought  he  worked  as 
well  as  on  the  water  days.  On  the  third  day,  however,  the  report  says 
that  he  had  palpitation  of  the  heart,  and  was  surprised  to  find  that  he 
was  obliged  to  stop  from  time  to  time  because  of  his  breathing  not 
being  so  good.  The  third  four  fluid  ounces  of  brandy,  taken  at  6  p.m., 
produced  on  all  three  days  very  marked  narcotic  effects.  The  account 
given  is  that  "  immediately  after  taking  it  he  became  heavy,  felt  the 
greatest  indisposition  to  exert  himself,  and  could  hardly  refrain  from 
throwing  down  his  spade  and  giving  up  his  work.  He  worked  with 
no  vigor,  and  on  the  second  evening  thought  his  muscular  power  was 
decidedly  lessened.  On  the  third  evening  it  was  raining ;  he  could 
not  dig,  but  took  walking  and  running  ex3rcise  under  cover.  On 
attempting  to  run,  he  found,  to  his  great  surprise,  as  he  is  a  particu- 
larly fast  and  good  runner,  that  he  could  not  do  so.  He  had  palpita- 
tion, and  got  out  of  breath,  and  was  obliged  to  stop." 

The  experience  of  this  man  harmonizes  with  the  advice  that  is  given 
by  guides  and  others  who  are  in  the  habit  of  undertaking  the  ascent 
of  mountains.  Spirits,  they  say,  take  away  the  strength  from  the  legs, 
and  should,  therefore,  be  avoided  during  a  fatiguing  expedition. 

Some  further  evidence  has  also  recently  been  published  by  Dr. 
Parkes,  upon  the  subject  under  consideration,  drawn  from  the  expe- 
rience of  the  Ashanti  campaign  of  1874.  In  an  introduction  to  the 
report  he  says  :  "  The  first  effect  of  alcohol,  when  given  during  a  march 
In  a  moderate  dose  (for  example,  what  is  equal  to  one  fluid  ounce  of 
absolute  alcohol,  the  amount  contained  in  about  two  and  a  half  fluid 
ounces  of  ordinary  spirits),  is  reviving,  but  this  effect  is  transient. 
The  reviving  effect  goes  off  after,  at  the  utmost,  two  and  a  half  miles 
of  additional  march,  and  sometimes  much  before  this  ;  then  the  previ- 
ous languor  and  sense  of  exhaustion  not  only  return,  but  are  some- 
times more  intense;  and  if  alcohol  is  again  resorted  to,  its  effects  now 


APPK.MJlX.  189 

are  less  satisfactory.  Its  reviving  power  is  usually  not  so  marked,  and 
its  peculiar  ansesthetic  and  narcotizing  influence  can  often  be  distinctly 
traced.  The  men  feel  heavy,  dull,  disinclined  to  march,  and  are  less 
willmg  and  cheerful." 

Whilst  the  general  testimony  resulted  in  condemnation  of  the 
employment  of  spirits  as  a  restorative  during  the  fatigue  of  marching, 
the  evidence  on  the  other  hand  went  strongly  to  show  that,  issued 
after  the  day's  fatigue  w^as  over,  the  spirit-ration  exerted  a  beneficial, 
reviving  effect,  and  afterward  induced  an  increased  feeling  of  warmth, 
accompanied  by  the  promotion  of  sleep.  Upon  these  points  Corporal 
Hindley,  who  had  been  always  a  temperate  man  and  never  in  the 
habit  previously  of  taking  spirits,  expressed  himself  as  follows  :  "  Had 
two  rations  of  rum  (a  ration  equal  to  two  and  a  half  fluid  ounces)  on 
the  way  to  the  Prah,  taken  in  the  evening  just  before  going  to  bed. 
Thought  it  useful ;  when  there  was  no  issue,  felt  chilly  and  cold  at 
night;  felt  warmer  when  he  had  taken  the  rum,  and  slept  better;  had 
no  doubt  about  sleeping  w'armer  and  feeling  better.  On  the  next  day 
felt  no  ill  effects  from  the  rum." 

The  writings  of  Dr.  Anstie  and  Dr.  Parkes  agree  in  assigning  about 
one  fluid  ounce  of  absolute  alcohol,  which  is  equivalent  to  two  and  a 
half  fluid  ounces  of  ordinary  spirits,  as  the  limit  of  moderation  for 
a  dose,  or  the  quantit}^  that  c^n  be  disposed  of  in  the  organism  of 
an  adult  male  without  producing  any  perceptible  injurious  effect  upon 
the  bodily  functions.  Up  to  this  quantity  its  action  is  that  of  a  stimu- 
lant ;  but  beyond,  it  begins  to  exert  a  narcotizing  influence,  and  when 
taken  to  excess,  a  more  or  less  profound  state  of  narcotism,  as  common 
observation  but  too  abundantly  testifies,  may  be  induced.  The  effects 
now  witnessed  upoif  the  general  system  are  no  longer  those  of  a  stimu- 
lant, but  exactly  the  reverse,  and  hence  to  describe  its  action  in  large 
doses,  it  may  be  spoken  of  as  a  depressant  and  narcotic. 

It  has  been  stated  i  that,  when  consumed  in  moderate  quantity,  the 
alcoholic  beverages  appear  to  encourage  the  appetite  and  promote 
digestion.  Taken  in  excessive  quantity,  however,  nothing  with  greater 
certainty  destroys  the  appetite  and  impairs  digestion. 

[The  author  of  the  present  work  would  add  that  the  Ashanti 
expedition  offered  peculiar  advantages  for  ascertaining  the 
truth  in  regard  to  the  question  before  us.     The  climate  of  the 

1  i.e.,  by  the  author  here  quoted. 


190  APPENDIX. 

country  is  so  unwholesome  for  Europeans  that  no  English  force 
could  have  lived  in  it,  except  during  the  few  weeks  of  the 
comparatively  healthy  season.  To  insure  the  health  of  the 
army,  the  government  consulted  the  best  medical  authority 
upon  all  points,  and  followed  their  advice  with  remarkably 
good  success.  The  use  of  spirits  by  the  men  was  entirely  under 
control.] 

THE  ABUSE  OF  ALCOHOL  AND  TOBACCO   IN  YOUTH. 

Thomas  More  Madden,  M.D.,F.R.C.S.,  Dublin,  President  of  the  Obstetric  Section  of  the 
British  Medical  Association.  In  "  Cyclopedia  of  the  Diseases  of  Children,"  Lippin- 
cott,  1889,  Vol.  I.,  p.  411. 

The  painful  exhibitions  of  juvenile  drunkenness  daily  witnessed, 
especially  among  the  neglected  street  Arabs,  who  during  or  even  before 
the  first  stage  of  puberty  are  forced  into  the  thoroughfares  of  our  great 
cities,  there  to  eke  out  a  living  as  best  they  may,  the  pathological  con- 
sequences of  whose  acquired  or  inherited  alcoholism  are  brought  under 
clinical  observation  in  the  form  of  gastric  and  hepatic  disorders,  and 
especially  cirrhosis  of  the  liver,  as  well  as  in  the  protean  forms  of  cere- 
bro-spinal  disease,  and  the  various  neuroses  which  are  so  frequently 
noticed  in  hospitals  for  children. 

In  the  British  Medical  Journal  and  elsewhere  I  have  I'eported  several 
instances  of  juvenile  alcoholism  that  came  under  my  care  in  the  Chil- 
dren's Hospital,  and  latterly  some  deaths  from  this  cause  have  occurred 
among  mere  lads.  In  the  majority  of  cases  of  juvenile  alcoholism, 
this  tendency  appears  inherited,  and  is  most  marked  in  those  whose 
mothers  were  inebriates,  —  intemperance  in  women  also  bearing  in 
other  ways  on  the  diseases  treated  in  hospitals  for  children,  where  its 
effects  are  strikingly  evinced  by  the  moral  and  physical  deterioration 
of  the  offspring  of  the  drunken,  and  by  their  special  predisposition  to 
strumous,  tubercular,  and  other  constitutional  taints. 

The  evil  thus  resulting  from  the  prevailing  intemperance  of  the 
young  as  well  as  the  old  should  induce  us  to  warn  those  whom  our 
counsel  may  influence  against  that  custom  of  giving  alcoholic  stimu- 
lants to  children,  which  is  so  general  in  its  practice  among  all  classes 
and  so  calamitous  in  its  results.  Even  in  those  exceptional  cases  in 
which  such  stimulants  may  be  necessary,  we  should  never  sanction 
their  administration  save  under  the  guise  and  in  the  definite  doses  of 


APPENDIX.  191 

other  remedial  agents ;  and  my  experience  in  hospital  and  private 
practice,  at  home  and  abroad,  has  amply  confirmed  the  view  expressed 
in  a  work  of  mine  published  many  years  since,  that  il  is  physiologically 
icrong,  as  well  as  morally  wijustijiable,  ever  to  allow  a  healthy  youth  to 
taste  alcohol  in  any  for  in} 

With  regard  to  the  effects  of  the  abuse  of  tobacco  during  early 
puberty,  of  which  we  see  so  many  instances,  especially  among  the 
neglected  children  of  the  poor,  I  may  refer  to  an  observation  I  long 
before  made  on  the  stunted  and  prematurely  aged  appearance  of  chil- 
dren in  Portugal,  where  smoking  is  indulged  in  from  the  earliest  pos- 
sible age.  There,  in  the  streets  of  Lisbon,  I  have  ofte*i  seen  with 
astonishment  boys  obviously  nmch  under  the  age  of  puberty  gravely 
sucking  a  strong  cigar  with  apparently  the'  same  gusto  which  our  less 
precocious  progeny  derive  from  the  forbidden  delights  of  the  sugar- 
stick.  There  can  be  no  doubt  that  the  influence  of  the  nicotine  thus 
absorbed  must  be  most  injurious  at  this  age ;  and  this  is  evident  in  the 
physical  aspect  of  the  j^ouths  referred  to. 


MEDICAL  OPINION    OF  ALCOHOL. 

William  H.  Draper,  Annual  Discourse  delivered  before  the  Xew  York  Academy  x)f  Medi- 
cine, Xov.  8,  1886.     "  Xew  York  Medical  Record,"  Xov.  27,  1886. 

I  believe  I  am  speaking  within  bounds  when  I  say  tliat  the  majority 
of  thoughtful  physicians  who  have  studied  carefully  the  effects  of  what 
is  regarded  as  the  moderate,  as  well  as  the  immoderate,  use  of  alco- 
holic beverages,  are  persuaded  that  as  foods,  excepting  possibly  in  the 
febrile  states,  their  value  has  been  largely  over-estimated,  and  that  in 
the  normal  condition  of  the  body  they  are  not  only  quite  mmecessary 
to  the  maintenance  of  healthy  nutrition,  but  are  always  more  or  less 
baneful  in  their  effects.  That  they  add,  as  Matthew  Arnold  has  said, 
to  the  agreeableness  of  life,  that  their  use  is  universal,  that  through 
their  stimulating  influence  upon  the  nervous  centres  they  have  been 
potent  factors  in  the  progress  of  civilization,  and  that  they  are  of  ines- 
timable value  as  stimulants  and  anaesthetics,  are  considerations  entirely 
apart  from  the  facts  concerning  them  which  are  especially  interesting; 
namely,  their  effects  on  nutrition ;  that  these  are  harmful  and  deteri- 
orating to  such  a  degree  as  to  constitute  the  most  powerful  cause  of 

1  Italics  by  author  of  this  book. 


192  APPENDIX. 

physical  degeneration  at  the  present  day,  there  can,  I  think,  be  no 
question.  The  drift  of  professional  opinion  in  this  country  and  in 
Europe  is  surely  tending  toward  the  restriction  of  their  use  as  articles 
of  diet,  and  simply  for  the  reason  that  they  are  the  determining  cause 
of  many  functional  derangements  and  structural  degenerations. 

EXPOSURE  TO  YELLOW  FEVER. 

When  persons  are  exposed  to  yellow  fever,  "  Spirituous  liquors,  if 
used  at  all,  should  be  taken  in  great  moderation.  Nothing  is  more 
likely  to  develop  an  attack  than  alcoholic  excesses,  and  the  habitual 
drunkard  is  almost  doomed  to  death  if  he  falls  sick  with  this  disease." 
—  From  Prize  Essay  by  G-eorge  M.  Sternberg,  M.D.,  U.  S.  Army; 
published  by  the  American  Public  Health  Association  in  1886. 

CIGARETTES. 

The  following  is  extracted  from  a  report  addressed  by  Willis  G. 
Tucker,  Analyst  to  the  New  York  State  Board  of  Health,  under  date 
of  Feb.  28,  1888:  — 

"  No  traces  of  opium  or  arsenic,  nor  evidence  of  the  presence  of  any 
other  poisonous  substance  foreign  to  the  tobacco,  was  discovered  in 
any  of  the  [brands  of  cigarettes  examined] . 

"  Should  stress  be  laid  upon  the  fact  that  several  deaths  have  been 
attributed  to  the  use  or  abuse  of  cigarettes  within  the  last  few  years, 
it  should  be  remembered  that  in  none  of  these  cases,  so  far  as  I  am 
aware,  has  it  been  claimed  that  the  harmful  effect  was  produced  by 
any  foreign  substance.  On  the  contrary,  it  has  been  attributed  to  the 
influence  of  the  tobacco  upon  the  nervous  system  and  heart,  there 
being  little  doubt  that  the  excessive  use  of  tobacco  may  work  irrep- 
arable injury  in  some  cases.  And  herein  lies  the  chief  danger  from 
the  use  of  cigarettes.  Being  small,  easily  carried  about,  inexpensive, 
and  everywhere  obtainable  of  good  quality,  which  is  by  no  means  the 
case  with  cigars,  they  are  doubtless  more  likely  to  be  used  to  excess 
than  is  tobacco  in  any  other  form ;  and  since  cigarette-smokers  usu- 
ally inhale  the  smoke,  the  products  of  the  combustion  of  the  tobacco 
more  readily  and  rapidly  gain  access  to  the  system  by  direct  absorption 
into  the  circulation  than  when  used  in  any  other  way.  Cigarettes  are 
objectionable  likewise  because  more  likely  to  be  smoked  by  children  ; 
and  whatever  may  be  said  concerning  the  effect  of  tobacco  on  adults, 


APPENDIX.  193 

all  authorities  agree  in  the  statement  that  it  exercises  a  baneful  effect 
upon  the  young."  —  Ninth  Annual  Report  of  New  York  State  Board 
of  Health,  pp.  516-518. 

ALCOHOL  AS  AN  ARTICLE  OF  DIET. 

"  A  Manual  of  Practical  Hygiene,"  by  E.  A.  Parkes  and  F.  S.  B.  de  Chaumont.     Sixth 
edition,  1883  (Blakiston,  Son  &  Co.). 

The  subject  is  treated  at  considerable  length  in  this  work.  The 
follov/ing  extracts  are  quoted  from  the  conclusions  reached  :  — 

"The  obvious  useful  physiological  actions  of  alcohol  are  an  improve- 
ment in  appetite,  produced  by  small  quantities,  and  an  increased 
activity  of  the  circulation,  which,  within  certain  limits,  may  be  bene- 
ficial. It  is  difficult  to  perceive  proof  at  present  of  any  other  useful 
action,  since  it  is  uncertain  whether,  during  its  partial  destruction  in 
the  system,  it  gives  rise  to  energy."    p.  296. 

"It  maybe  considered,  then,  that  the  limit  of  the  useful  effect  is 
produced  by  some  quantity  between  1  and  1|  fluid  ounces  [of  alco- 
hol] in  twenty-four  hours.  .  .  .  For  children  there  is  an  almost  uni- 
versal consent  that  alcohol  is  injurious,  and  the  very  small  quantity 
which  produces  intoxication  in  them  indicates  that  they  absorb  it 
rapidly  and  tolerate  it  badly."    p.  286. 

"  There  is  no  difficulty  in  proving,  statistically,  the  vast  loss  of 
health  and  life  caused  by  intemperance ;  and  the  remarkable  facts  of 
the  Provident  Institution  show  the  great  advantage  total  abstainers 
have  over  those  who,  though  not  intemperate,  use  alcohol  more  freely. 
But  it  is  almost  impossible,  at  present,  to  compare  the  health  of  teeto- 
tallers with  those  who  use  alcohol  in  the  moderate  scale  given  above 
[see  previous  paragraph].  In  both  classes  are  found  men  in  the 
highest  health,  and  with  the  greatest  vigor  of  mind  and  body;  in 
both  are  to  be  found  men  of  the  most  advanced  age.  If  the  question 
is  looked  at  simply  as  a  scientific  one,  it  is  hardly  possible  at  present 
to  give  an  answer."    p.  297. 

"  The  facts  now  stated  make  it  difficult  to  avoid  the  conclusion  that 
the  dietetic  value  of  alcohol  has  been  much  over-rated.  It  does  not 
appear  possible  at  present  to  condemn  alcohol  altogether  as  an  article  of 
diet,  or  to  prove  that  it  is  invariably  hurtful,  as  some  have  attempted 
to  do.  It  produces  effects  which  are  often  useful  in  disease  and  some- 
times desirable  in  health,  but  in  health  it  is  certainly  not  a  necessity, 
and  many  persons  are  much  better  without  it.    As  now  used  by  man- 


194  APPENDIX. 

kind  (at  least  in  our  own  and  many  other  countries)  it  is  infinitely 
more  powerful  for  evil  than  for  good ;  and  though  it  can  hardly  be 
imagined  that  its  dietetic  use  will  cease  in  our  time,  yet  a  clearer  view 
of  its  effects  must  surely  lead  to  a  lessening  of  the  excessive  use  which 
now  prevails."    p.  305. 

[It  may  be  added  that  tlie  vs^ork  here  quoted  from  is  prob- 
ably at  present  the  highest  authority  upon  general  hygiene  in 
our  language.  It  is  particularly  emphatic  in  condemning  the 
use  of  alcoholic  drink  in  military  or  naval  life.] 


APPENDIX   II. 

DISSECTION   OF  ANIMALS. 

If  the  teacher  is  willing  to  take  a  little  additional  trouble,  he  will 
find  himself  well  repaid  by  a  view  of  the  internal  organs  of  a  small 
animal,  as  the  dog,  cat,  or  rabbit.  It  is  best,  of  course,  to  go  through 
with  the  dissection  privately  before  attempting  to  dissect  for  a  class. 
The  work  does  not  require  muscular  strength,  for  the  parts  yield 
readily  to  a  sharp  knife,  and  even  the  ribs  are  easily  cut  through  with 
strong  scissors  or  nippers. 

The  apparatus  required  for  the  dissection  is  a  good-sized  tray,  a 
towel,  basin  of  water,  fine  string,  small  blow-pipe,  light,  sharp  knife, 
light  forceps,  common  blunt-pointed  scissors. 

Any  small  animal  will  serve  the  purpose.  The  cat,  however,  is  often 
the  most  convenient.  A  painless  death  is  secured  by  chloroform. 
Professor  Wilder,  in  his  very  thorough  work  "  Anatomical  Technol- 
ogy of  the  Cat,"  recommends  the  use  of  a  tight  box  with  a  slid- 
ing door ;  the  bag  containing  the  cat  is  opened  in  such  a  way  as  to 
allow  the  animal  to  enter  the  door,  —  which  she  proceeds  to  do  with- 
out fuss ;  the  door  is  then  shut ;  a  sponge  containing  two  teas]30onf uls 
of  chloroform  is  quickly  inserted,  and  in  a  few  minutes  life  peacefully 
departs. 

The  animal  being  laid  on  his  back,  and  the  paws  stretched  and  tied 
to  any  convenient  objects,  the  knife  is  passed  under  the  skin  at  the 
chin,  and  the  skin  is  divided  by  one  cut  straight  down  to  the  lower 
part  of  the  belly,  without  injuring  the  muscles.  The  skin  is  then 
pulled  off  with  the  fingers  to  the  right  and  left,  with  the  aid  of  light 
strokes  of  the  knife.  The  cartilages  of  the  ribs  are  readily  seen  in 
front.  Cut  them  near  where  they  join  the  ribs.  Raise  the  cartilages 
as  one  piece,  exposing  the  heart  and  lungs.  Avoid  injuring  the  lungs  ; 
but,  to  provide  against  that  accident,  you  may  inflate  the  lungs  at  this 
stage  by  passing  the  tube  into  the  trachea  and  blowing;  they  will 
shrink  to  a  small  compass  afterwards,  and  leave  you  free  to  disengage 
the  heart.  This  operation  should  be  done  carefully,  tying  the  aorta 
and  the  two  vense  cavse  twice,  and  cutting  between  the  ligatures  to  pre- 
vent bleeding.     The  organ  closely  resembles  that  of  man  in  form. 

195 


196  APPENDIX. 

After  studying  its  outward  appearance  with  the  aid  of  the  plates,  you 
may  remove  the  ligatures  and  wash  out  the  blood  with  a  fine  syringe, 
introduced  at  each  auricle ;  after  which,  if  you  choose,  fill  the  cavities 
with  alcohol  of  ninety-five  per  cent  strength,  tie  the  orifices,  and  sus- 
pend the  heart  in  alcohol  for  two  days  by  a  pin  passed  through  the  tip 
of  the  organ.  Windows  can  then  be  cut  with  a  knife  in  the  hardened 
tissue  so  as  to  show  the  interior  and  the  valves  beautifully. 

The  lungs  can  be  removed  and  put  in  water  to  observe  their  light- 
ness. The  diaphragm  is  now  in  a  convenient  position  for  study. 
Afterwards  the  abdominal  cavity  should  be  opened  by  a  cut  through 
the  muscles  in  front,  when  the  stomach  is  seen  just  below  the  dia- 
phragm, with  the  intestines,  and  at  one  side  the  liver.  Behind  the 
mass  of  intestines  lie  the  two  kidneys,  and  lower  down  the  bladder 
(which  should  have  been  emptied  previously,  to  prevent  disagreeable 
accidents).  The  stomach  can  be  opened  without  causing  serious 
offence  to  the  senses,  most  conveniently  by  a  cut  along  the  large 
curvature.  Continuing  through  the  pylorus  into  the  small  intestine, 
we  find  the  character  and  odor  of  the  contents  at  once  changed. 

The  gall-bladder,  the  internal  structure  of  the  liver,  kidneys,  spleen, 
and  pancreas,  can  be  examined  with  ease.  The  circulation  in  the 
great  network  which  holds  the  intestines  in  place  is  easily  seen,  con- 
verging towards  a  point  near  the  liver. 


APPENDIX   III. 

TREATMENT    OF   THE    DROWNED.^ 

Two  Things  to  be  done  :  Restore  Breathing  ;  Restore 
Animal  Heat. 

Rule  1. — -Remove  all  obstructions  to  breathing.     Instantly 

loosen  or  cut  apart  all  neck  and  waist  bands ;  turn  the  patient  on  his 
face,  with  the  head  down  hill ;  stand  astride  the  hips  with  your  face 
towards  his  head,  and,  locking  your  fingers  together  under  his  belly, 


Fig.  1. 

raise  the  body  as  high  as  you  can  without  lifting  the  forehead  off  the 
ground  (Fig.  1),  and  give  the  body  a  smart  jerk  to  remove  mucus 
from  the  throat  and  water  from  the  windpipe;  hold  the  body  sus- 
pended long  enough  to  slowly  count  one,  two,  three,  four,  five, 
repeating  the  jerk  more  gently  two  or  three  times. 

Rule  2.  —  Place  the  patient  on  the  ground  face  downward,  and, 
maintaining  all  the  while  your  position  astride  the  body,  grasp  the 
points  of  the  shoulders  by  the  clothing,  or,  if  the  body  is  naked,  thrust 
your  fingers  into  the  armpits,  clasping  your  thumbs  over  the  points  of 
the  shoulders,  and  raise  the  chest  as  high  as  you  can  (Fig.  2)  with- 

1  As  given  by  the  Michigan  State  Board  of  Health. 

197 


198 


APPENDIX. 


out  lifting  the  head  quite  off  the  ground,  and  hold  it  long  enough  to 
slowly  count  one,  two,  three.  Replace  him  on  the  ground,  with  his 
forehead  on  his  flexed  arm,  the  neck  straightened  out,  and  the  mouth 


Fig.  2. 


and  nose  free.      Place  your  elbows   against  your  knees,   and  your 
hands  upon  the  sides  of  his  chest  (Fig.  3)  over  the  lower  ribs,  and 


^^^^'~. 


Fig.  3. 


press  downward  and  inward  with  increasing  force  long  enough 
to  slowly  count  one,  two.  Then  suddenly  let  go,  grasp  the  shoul- 
ders as  before,  and  raise  the  chest  (Fig.  2)  ;  then  press  upon  the  ribs, 


APPENDTX.  199 

etc.  (Fig.  3).  These  alternate  movements  should  be  repeated  10  or 
15  times  a  minute  for  an  hour  at  least,  miless  breathing  is  restored 
sooner.     Use  the  same  regularity  as  in  natural  breathing. 

Rule  3.  —  After  breathing  has  commenced,  restore  the  animal 
HEAT.  AVrap  him  in  warm  blankets,  apply  bottles  of  hot  water,  hot 
bricks,  or  anything  to  restore  heat.  Warm  the  head  nearly  as  fast  as 
(he  hodij,  lest  convulsions  come  on.  Rubbing  the  body  with  warm  cloths 
or  the  hand,  and  slapping  the  fleshy  parts,  may  assist  to  restore  warmth, 
and  the  breathing  also.  If  the  patient  can  surely  swallow,  give  hot 
coffee,  tea,  milk,  or  a  little  hot  sling.  Give  spirits  sparingly,  lest  they 
produce  depression.  Place  the  patient  in  a  warm  bed,  and  give  him 
plenty  of  fresh  air ;  keep  him  quiet. 

BEWARE! 

Avoid  Delay.  A  momext  may  turn  the  scale  for  life  or  death. 
Dry  ground,  shelter,  warmth,  stimulants,  etc.,  at  this  moment  are 
nothing  —  artificial  breathing  is  everything,  —  is  the  one 
remedy,  —  all  others  are  secondary. 

Do  not  stop  to  remove  wet  clothing.  Precious  time  is  wasted, 
and  the  patient  may  be  fatally  chilled  by  exposure  of  the  naked  body, 
even  in  summer.  Give  all  your  attention  and  effort  to  restore  breath- 
ing by  forcing  air  into,  and  out  of,  the  lungs.  If  the  breathing  has 
just  ceased,  a  smart  slap  on  the  face  or  a  vigorous  twist  of  the  hair 
will  sometimes  start  it  again,  and  may  be  tried  incidentally. 

Before  natural  breathing  is  fully  restored,  do  not  let  the  patient  lie 
on  his  back  unless  some  person  holds  the  tongue  forward.  The  tongue 
by  falling  back  may  close  the  windpipe  and  cause  fatal  choking. 

Prevent  friends  from  crowding  around  the  patient  and  exclud- 
ing fresh  air ;  also  from  trying  to  give  stimulants  before  the  patient 
can  swallow.     The  first  causes  suffocation  ;  the  second,  fatal  choking. 

Do  NOT  GIVE  UP  TOO  SOON :  You  are  working  for  life.  Any  time 
within  two  hours  you  may  be  on  the  very  threshold  of  success  without 
there  being  any  sign  of  it. 

In  suffocation  by  smoke  or  any  poisonous  gas,  as  also  by 
hanging,  proceed  the  same  as  for  drowning,  omitting  effort  to  expel 
water,  etc.,  from  windpipe. 

In  suspended  breathing  from  effects  of  chloroform,  hydrate 
of  chloral,  etc.,  proceed  by  Rule  2,  taking  especial  pains  to  keep  the 
head  very  low,  and  preventing  closure  of  the  windpipe  by  the  tongue 
falling  back. 


INDEX. 


Abdomen,  14. 

Abdominal  respiration,  63. 

Absorption  of  fluids,  143. 

Accommodation,  155,  156. 

Acid  drinks,  87. 

Acids,  effect  on  teeth,  91, 172. 

Adam's  apple,  124. 

Age,  as  affecting  the  bones,  9, 10, 15, 16, 
22  ;muscles,39;  digestion, 93;  endur- 
ance of  cold,  GG ;  eyes,  15G ;  jaw,  170. 

Air,  see  Lungs,  Ventilation. 

Albumin,  46,  78,  100. 

Alcohol,  chap.  11.  How  made,  175; 
uses,  176;  effects  in  general,  176; 
special,  181 ;  amounts  used,  189, 193 ; 
mentioned  by  Pavy,  187;  Anstie, 
189 ;  Parkes,  187-189, 193 ;  Madden, 
190;  Draper,  191;  effects  on  bones 
and  joints,  24;  muscles,  42;  cir- 
culation and  respiration,  69,  181; 
nervous  system,  143. 

American  faults  of  diet,  84,  87. 

Animal  food,  77,  78,  80. 

Ankle,  14. 

Antagonistic  muscles,  35. 

Aorta,  50. 

Appetite,  40,  88. 

Aqueous  humor,  153. 

Arteries,  49. 

Artificial  respiration,  63,  197. 

Ashanti  campaign,  188. 

Asleep  —  a  limb,  138. 

Asphyxia,  67. 

Auricle,  55. 

Ball  and  socket  joint,  19. 
Barley,  84. 


Bathing,  127, 128, 165. 

Beans,  82,  84. 

Bedding,  115. 

Beer,  175. 

Biceps,  34. 

Bicuspids,  168. 

Bile,  4. 

Bleeding,  68. 

Blindness,  159. 

Blisters,  109. 

Blood,   chap.   4.      Composition,    46; 

nutritive   power,  47;    loss  of,  48; 

vessels,  49 ;  venous  and  arterial,  52, 

61;  in  skin,  108-112;  in  brain,  140. 
Blood-vessels  in  bone,  6,  7;   in  skin, 

108,  114 ;  effects  of  alcohol,  181. 
Blushing,  62. 
Bones,  chap.  2. 
Bone-ash,  9. 
Bony  tissue,  2 ;  chap.  2. 
Bowels,  inflammation,  125. 
Bow-legs,  23. 
Brain,  132;  size,  134;  removal,  139; 

effect  of  alcohol,  144. 
Brandy,  176. 
Bread,  101. 
Breakfast,  89,  90. 
Breast-bone,  13. 
Breathing,  36;  see  Respiration. 
Bronchial  tubes,  60. 
Burns,  110. 
Butter,  83,  99. 

Caffein,  183. 
Cake,  91. 
Candy,  91. 
Canine  teeth,  168. 

201 


202 


INDEX. 


Capillaries,  49,  50,  114. 
Capsule  of  hip-joint,  17. 
Captain  Cook,  85. 
Carbo-hydrates,  78. 
Carbon,  78,  79,  84. 
Carbonic-acid,  61. 

"  "      water,  87. 

Cartilage,  9,  10,  16. 
Casein,  78. 
Cataract,  159. 
Cells,  1,  91 ;  of  cuticle,  108 ;  of  nervous 

system,  131,  132,  134,  140. 
Cementum,  169. 
Cerebellum,  132. 
Cerebral  ganglia,  132,  133. 

"       nerves,  136. 
Cerebro-spinal  system,  132. 
Cerebrum,  132. 
Cerumen,  162,  164. 
Cheese,  77,  84. 
Chemistry  of  the  body,  80,  81;    see 

Combustion,  Oxygenation. 
Chest,  13. 

"      development,  41,  63. 
Children,  see  Age. 
Chocolate,  182. 
Cider,  175. 
Cigarettes.  185,  192. 
Circulation,  chap.  4.    Stoppage  of,  47, 

67;  general  system,  49-52;  portal, 

56;  pulmonary,  54;  lymphatic,  56; 

affected  by  alcohol,  181. 
Cleaning  teeth,  91,  172. 
Climate  of  Europe,  178. 
Clot,  46. 

Clothing,  41,  67,  115,  128. 
Coagulation,  46,  100. 
Coarse  food,  85. 
Cocoa,  180. 

Coffee,  89,  90,  91,  96,  97,  182. 
Cold,  resistance  to ;  effect  of  alcohol, 

145;  of  tea  and  coffee,  184. 
Cold,  sensation  of,  113. 
Colds,  90,  125-128,  165. 
Cold  water,  87. 
Collar-bone,  15. 
Combustion,  60,  68,  80,  83. 


Components  of  body,  91. 
Concha.  162. 
Consciousness,  135. 
Consumption,  126. 
Contortionists,  19. 
Convolutions  of  brain,  132. 
Cooking,  98. 
Corium,  111. 
Cornea,  152. 159. 
Corpuscles  of  blood,  46,  48. 
Cotton  clothing,  115. 
Cough,  65.  113,  139. 
Crime,  146,  180. 
Crown  of  tooth,  169. 
Crusta  petrosa,  169. 
Crustacea,  22. 
Crystalline  lens,  154. 
Cutting-teeth,  167. 

Deafness,  125,  165. 

Decayed  teeth,  170,  172. 

Delirium  tremens,  179. 

Deltoid,  35. 

Dentine,  169. 

Derma,  108. 

Diaphragm  in  breathing,  63. 

Diet,  79,  82,  83. 

Digestion,  91-94. 

Dinner,  90. 

Dirt  "wholesome,"  117. 

Dissection,  27, 45, 150, 174.   Appendix. 

Drink,  86,  99. 

Drinking,  93. 

Drowning,  197. 

Drum,  162. 

Dyspepsia,  87,  89,  96,  97,  99-102 ;  from 

tea  and  coffee,  183 ;  from  alcoholic 

drink,  181, 189,  190. 

Ear,  chap.  10. 
Earache,  125. 
Ear-muscles,  36. 
Ear-wax.  162, 164. 
Eating,  time  for,  41. 
Eggs,  77,  78,  100. 
Elasticity  of  bones,  10. 
Elements  of  food.  78. 


INDEX. 


208 


Emulsion,  94. 
Enamel,  169,  170. 
Epidermis,  108-112. 
Epithelial  tissue,  2. 
Essential  oils,  96, 
Eustachian  tube,  163. 
Excretion,  4,  47. 
Excess  in  eating,  88. 
Exclusive  diet,  79,  83. 
Exercise,  40,  41,  06. 
Expression,  37. 
Eye,  chap.  9. 

Eyelashes  and  eyelids,  152. 
Eye-muscles,  36. 
Eye-tooth,  167. 

Fainting,  69. 

Far-sight,  157. 

Fat,  78,  83,  84,  94,  101,  102. 

Fatigue,  bathing  during,  119. 

Fattening  food,  84. 

Fatty  tissue,  2,  30. 

Feathers,  115. 

Fermentation,  175. 

Fever,  prevention,  90. 

Fibres,  1 ;  of  muscle,  32,  39 ;  of  nerve, 
131,  13i. 

Fibrin,  41. 

Fibrous  tissue,  2,  18. 

Filling  teeth,  170. 

Finger-joints,  20. 

Fish,  82. 

Flavor,  95,  183. 

Flesh,  31,  32. 

Fluids  of  body,  3. 

Food,  chap.  5;  classes,  77-79;  purpose 
and  use,  80;  effects  and  values,  81- 
85 ;  liquid,  86 ;  amount,  88 ;  habits,  89. 

Fracture,  23. 

Frying,  99,  102. 

Ganglia,  132, 136. 
Ganglionic  system,  132,  136. 
Gastric  juice,  4,  93. 
Gelatin,  9,  78,  79. 
General  circulation,  55. 
General  sensation,  138. 


Gin,  176. 

Glands,  3,  4,  94. 

Glasses,  154,  157,  158. 

Gliding-joint,  19. 

Glottis,  122. 

Glue,  78. 

Gluten,  78,  82. 

Gout,  24. 

Graminivora  and  granivora,  169. 

Gravy,  102. 

Gray  nervous  matter,  132,  134. 

Grinders,  168. 

Gristle,  see  Cartilage. 

Growth  of  body,  80 ;  see  Age. 

Habit  of  using  narcotics,  146. 

Hair,  110. 

Hearing.  163. 

Heart,  49,  70,  183 ;  effects  of  tea  and 

coffee,  184;  of  tobacco,  70,  184;   of 

alcohol,  69,  70,  177. 
Heat,  81. 

"     sensation  of,  113. 
Hiccough,  65. 
Hinge-joint,  20. 
Hip-joint,  19,  20. 
Horny  stratum  of  skin,  109. 
Hot  water,  87. 
Hydrogen,  78,  79,  84. 
Hygiene  defined,  22. 

Ice-water,  87. 

Incisors,  167. 

Indigestible  parts  of  food,  85. 

Indigestion,  142;  see  Dyspepsia. 

Infants'  bones,  9, 15,  16,  22 ;  muscles, 

39;  digestion,  93. 
Inflammation  of  eye,  125,  159. 
Influenza,  125. 
Inheritance,  23. 
Innominate  bones,  14,  15. 
Insanity,  179. 
Insects  in  ear,  165. 
Intestines,  92-94. 
Intoxication,  176;  see  Alcohol 
Involuntary  muscles,  38. 
Involuntary  motion,  139. 


204 


INDEX. 


Iris,  152. 

Iron  as  medicine,  48. 

Jaws,  20. 

Jelly,  78. 
JeUy-fish,  22. 

Joints,  chnp.  2.  Structure,  16 ;  classes, 
19. 

Kidneys,  4,  181. 
Knee-pan,  14. 
Knock-knees,  23. 

Labyrinth,  162. 

Larynx,  122. 

Lens  of  eye,  154, 159. 

Levers,  10,  35. 

Life  of  a  plant,  2,  23 ;  of  a  bone,  7,  8 ; 
related  to  skeleton,  22. 

Ligaments,  17-19;  round,  19. 

Light  passing  to  retina,  154. 

Limbs,  14. 

Lime,  9,  22. 

Lime-juice,  85. 

Linen,  115. 

Liver,  4,  94;  circulation,  56;  inflam- 
mation, 125;  affected  by  alcohol, 
181,  190. 

Locomotion,  36. 

Lunch,  70. 

Lungs,  59. 

Lymph,  3. 

Lymphatic  vessels  and  glands,  56,  57. 

Maize,  77,  82. 

Mammalia,  22. 

Marrow,  7,  9,  27. 

Meals,  time,  89. 

Meat,  77-79,  82-84,  88,  89. 

Meatus,  162. 

Membranes,  2,  3. 

Milk,  23,  46,  77,  78,  82,  84. 

Milk-teeth,  168. 

Mind,  133,  134, 140  ;  effect  of  alcohol, 

144,  145,  176,  177. 
Mineral  components  of  body,  9,  22. 
Mineral  food,  77,  78,  80,  95. 


Mixed  diet,  99,  100. 

Molars,  168. 

Motion,  135-140. 

Mucous  membrane,  2,  4,  94,  152. 

Mucus,  4. 

Muscles,  chap.  3;  pages  46,  81.  An 
tagonists,  35;  of  breathing,  35;  o\ 
blood-vessels,  39 ;  of  expression,  37 , 
of  eyeball,  156;  involuntary,  38;  o) 
intestine,  94;  of  larynx,  123;  oi 
speech,  35;  of  stomach,  39;  func 
tions  depend  on  nerves,  130;  effect 
of  alcohol,  176. 

Music,  122. 

Myosin,  78. 

Nails,  109-111. 

Xarcotics,  chap.  12;  144,  146. 
Near-sight,  154, 156, 157. 
Neck,  broken,  139. 
Neck  of  tooth,  169. 
Nerves,  chap.  8.  Function,  136-138;  of 
skin.  111 ;  of  hearing,  164 ;  optic,  159. 
Nervousness,  183,  185. 
Nitrogen,  78,  79,  82. 
Nucleus  of  cell,  1. 

Oatmeal,  oats,  77,  82,  88. 
Oil,  77,  78;  for  the  toilet,  118;  vola- 
tile, 183. 
Old-sight,  156. 
Onion,  85. 
Opium,  146. 
Over-eating,  88,  89. 
Oxidation,  60. 
Oxygen,  78,  79,  84. 
Oxygenation,  56,  59,  60. 

Pain,  113,  130,  138. 
Palpitation,  71,  183, 185. 
Pancreas,  4,  94,  95. 
Papillae  of  skin,  112. 
Paralysis,  139,  141. 
Parotid  gland,  4. 
Peas,  78,  82,  83. 
Pectoral  muscle,  35. 
Pelvic  girdle,  15. 


INDEX. 


205 


Pelvis,  U, 

Perception  of  light,  151 ;  of  sound,  164. 

Periosteum,  8. 

Perspiration,  ()1,  114-118;  see  Sweat. 

Phosphorus,  9,  21',  78,  79. 

Pie-crust,  99,  107. 

Pigeon-breast,  23. 

Pimples,  116. 

Pivot-joint,  19. 

Plant-structure,  2,  5. 

Play,  117. 

Pleasure,  130. 

Poisons  in  contact  with  skin,  117. 

Pores,  110,  116. 

Pork,  98. 

Portal  circulation,  56. 

Potato,  83. 

Protection  of  soft  i^arts,  10. 

Proteids,  78,  94,  95. 

Pulmonary  circulation,  55, 

"  vesicles,  60. 

Pulp-cavity  of  tooth,  169. 
Pulse,  49. 
Pupil,  152. 
Purulent  ophthalmia,  159. 

Raw  food,  97. 

Reaction  after  bathing,  118. 

Reading  aloud,  126. 

Reflex  motion,  139. 

Resi)iration,  chap.  4.    Apparatus,  59, 

62 ;  process,  62. 
Retina,  154. 
Rheumatism,  23. 
Ribs,  13. 
Rice,  83. 
Rickets,  23. 
Rodents,  168. 
Roman  bath,  118. 
Roots  of  nerves,  139. 

•*     "  teeth,  169. 
Round  ligament,  19. 
Rum,  176. 
Running,  66. 

Sacrum,  14-16. 
Saliva,  3,  93. 


Salt,  95,  96. 

Salt  meat,  85,  86. 

Scarlet  fever,  109. 

Scars,  110,  111. 

Sclerotic,  152. 

Scrofula,  23,  159. 

Scurvy,  85. 

Sea-bath,  118. 

Seats,  23. 

Sebaceous  glands,  110,  114, 116. 

Secretion,  4,  81;  depends  on  nerves, 
130. 

Sensation,  112,  137. 

Senses,  112,  1,30. 

Serum,  46. 

Shoulder-blades,  15. 

Shoulder-joint,  19. 

Sigh,  65. 

Singing,  124,  126. 

Skeleton,  12,  22. 

Skin,  chap.  6.  Structure,  1 ;  color,  109, 
111;  cells  of,  108;  functions,  112; 
affected  by  alcohol,  181. 

Skull,  11,  12,  21,  132. 

Sleep,  141-144. 

Smooth  muscular  fibre,  39. 

Sneezing,  65,  139. 

Soap,  117. 

Sobbing,  65. 

Soda-water,  87. 

Soldiers,  use  of  alcoholic  drink, 
187-189,  193. 

Sore  eyes,  159. 

Soup,  98,  100. 

Speech,  36, 141. 

Spices,  96,  99. 

Spine,  13,  21. 

Spinal  canal,  13. 
"      cord,  134. 
"      curvature,  23,  40. 
"      nerves,  136. 

Spirits,  176. 

Sprain,  23. 

Squinting,  156. 

Starch,  77,  78,  93-95,  100. 

Stimulants,  chap  11.  Effect  on  capil- 
laries, 69;  kidneys,  69;  respiration 


206 


INDEX. 


and  circulation,   69;    temperature, 

70 ;  heart,  75 ;  athletic  work,  70. 
Stomach,  4,  92-94 ;    muscles  of,  39  ; 

of  animals,  97. 
Straining  the  eyes,  155,  157,  158. 
Strength  of  bones,  10,  12. 
Structure,  general  elements,  chap.  1. 

Of  plants,  2 ;  of  body,  1. 
Study,  a  cause  of  near-sight,  156. 

"       time  for,  143,  158. 
Suffocation,  67. 
Sugar,  77,  78,  88,  91;  affecting  teeth, 

172. 
Sulphur,  78,  79. 
Sunburn,  109. 
Sunlight,  23. 
Sunstroke,  86. 

Support  of  body-weight,  10, 12,  14. 
Sutures,  12,  15. 
Swallowing,  38. 
Sweat,  3,  4 ;  see  Perspiration. 
Sweat-glands,  3,  110,  114. 
Sweetmeats,  84. 
Synovial  fluid,  16. 
sac,  18,  19. 

Taste,  95,  99. 

Tea,  coffee,  cocoa,  43,  90,  91,  97,  182. 

Teeth,  chap.  11.  Functions,  93;  af- 
fected by  sugar,  91 ;  of  animals,  97, 
168. 

Temperature  of  body,  61. 

*♦  "    room,  66,  127,  143. 

Tendon,  31,  34. 

Thein,  183. 

Thirst,  86. 

Tickling,  113. 

Tissues  in  general,  1,  2. 

Thorax,  14. 

Tobacco,  42,  43,  146,  184 ;  Madden  on, 
190. 

Toilet,  116. 

Toothpicks  and  brushes,  172. 

Touch,  112, 137 ;  impaired  by  alcohol, 
145. 


Trachea,  59. 
Training,  86. 
Transfusion  of  blood,  48. 
Trembling,  43. 
Trichinae,  98. 
Trunk,  13. 
Turkish  bath,  128. 
Tympanic  cavity,  162. 

Vaccination,  109. 

Valves  of  heart,  50,  54,  55;  of  veins 

53 ;  of  lymphatics,  56. 
Veins,  49,  50;  portal,  56;  vena  cava. 

56;  disease,  67;  valves,  53. 
Vegetable  food,  77,  78. 
Ventilation,  68,  76. 
Ventricle,  55. 
Vertebrse,  13,  14,  127,  143. 
Vertebral  column,  see  Spine. 
Vertebrata,  22. 
Vibrations,  164. 
Villi  of  intestine,  94. 
Visceral  system  of  nerves,  132,  136. 
Vitreous  humor,  154. 
Vocal  cords,  122. 
Voice,  chap.  7.    Of  boys,  124. 
Voluntary  motion,  138. 

Warm  food,  99. 

Washing,  109,  115,  118,  164. 

Waste-products  of  system,  see  Excre- 
tion. 

Water  in  body,  3,  86;  in  food,  86; 
amount  perspired,  114. 

Wheat,  83. 

Whiskey,  176. 

White  of  eye,  lf;2. 

Wilder  on  cat,  195. 

Windpipe,  59. 

Wine,  175,  178. 

Work,  36,  81,  90. 

Wrist,  14. 

Wounds  of  nerves,  135. 

Yellow  fever,  192. 


JUN  Z2    1928 


„^.,i^>>i>>>^vJi. 


